Damir Staresinic

Institute of Physics, Zagreb

The study of the transition from high-entropy alloys (HEAs) to conventional alloys (CAs) composed of the same alloying components is apparently important, both for understanding the formation of HEAs and for proper evaluation of their potential with respect to that of the corresponding CAs. However, this transition has thus far been studied in only...

Pulsed laser deposition technique was employed to grow thin films of K0.3MoO3 on Al2O3 (1-102) and SrTiO3 (510) substrates. Structural and imaging characterization revealed good quality films with well oriented grains of few microns in length. Both non-selective (transport) and order-selective (femtosecond pump-probe spectroscopy) probes revealed c...

The sliding of the room-temperature charge density wave (CDW) in the monoclinic phase of NbS3 under rf power is studied. The threshold field, Et, and Shapiro steps’ width, δE, show aperiodic Bessel-type oscillations as a function of rf voltage. Here we demonstrate experimentally that, if presented as a function of CDW path length in each half perio...

We report studies of the Seebeck coefficient S of the quasi-one-dimensional compound NbS3, together with the temperature dependence of its specific conductivity σs and heat capacity cp. The monoclinic phase (NbS3-II) is studied over the temperature range T=80–400 K, which covers two charge density wave (CDW) transitions at TP1=360 K (CDW-1) and TP2...

We have studied low temperature specific heat (LTSH) in different glass-forming metallic alloys: binary marginal glasses ZrNi [1], bulk metallic glasses CuHfTi [2] and high entropy metallic glasses TiZrNbCuNi(Co) [3]. The results concerning so-called boson peak (BP) contribution to the density of vibrational states in excess to the Debye contributi...

We report on the electrodynamic properties of the single crystalline lead-substituted M-type barium hexaferrite, Ba _0.3 Pb _0.7 Fe _12 O _19 , performed in the broad frequency range including radio-frequency, terahertz and sub-terahertz bands, which are particularly important for the development of microelectronic devices. We demonstrate how chang...

We have investigated correlation between thermodynamic parameters given by low-temperature heat capacity (Cp) measurements and glass forming ability (GFA) of NiZr and CuHfTi metallic glasses. Cp of metallic glasses at sufficiently low temperature deviates from the Debye T3 law with a very well known anomaly named Boson peak (BP) which can be observ...

The atomic structure, electronic structure, and physical properties of (TiZrNbCu)1−xNix (x ≤ 0.5) metallic glasses (MGs) were studied in both the high-entropy (0 < x < 0.35) and the higher Ni concentration range (x ≥ 0.35). Atomic structure studies performed with X-ray diffraction and synchrotron powder diffraction provided average atomic volumes,...

The atomic structure, electronic structure and physical properties of $(TiZrNbCu)_{(1-x)}Ni_x$ (x $\leq$ 0.5) metallic glasses (MG) were studied in both the high-entropy (0<x<0.35) and the higher Ni concentration range (x $\geq$ 0.35). Atomic structure studies performed with X-ray diffraction and synchrotron powder diffraction provided average atom...

Recent studies (J. Alloys Compd. 695 (2017) 2661) of the electronic structure and properties of $(TiZrNbCu)_{1-x}$$Ni_{x}$ (x$\leq$0.25) amorphous high entropy alloys (a-HEA) have been extended to x=0.5 in order to compare behaviours of a-HEA and conventional Ni-base metallic glasses (MG). The amorphous state of all samples was verified by thermal...

We present an experimental investigation of the fragility and heat capacity of metallic glass Zr77Ni23. The ribbon sample was produced by melt-spinning technique. Glass transition temperature Tg obtained by differential scanning calorimetry with various heating rates was used to estimate fragility parameter m. Heat capacity measurements were perfor...

Hard form of carbon obtained by collapsing C60 fullerene molecules at moderate pressure and temperature was investigated using different imaging techniques at spatial resolutions ranging from angstrom to millimeter. Hierarchical granular morphology has been observed from the atomic up to the sample size length scale, revealing scale independent gra...

The uniaxial strain of quasi-one-dimensional conductor whiskers of orthorhombic TaS3 at a strain higher than εc ~ 0.8% leads to a sharp increase in the coherence of the properties of a charge density wave (CDW), which manifests itself in its motion in fields higher than threshold field Et. During uniaxial elongation, TaS3 is shown to exhibit the fo...

DOI:https://doi.org/10.1103/PhysRevB.94.179904

A comprehensive study of selected properties of four (TiZrNbCu)1-xNix (x ≤ 0.25) amorphous high entropy alloys (a-HEA) has been performed. The samples were ribbons about 20 μm thick and their fully amorphous state was verified by X-ray diffraction and thermal analysis. The surface morphology, precise composition and the distribution of components w...

We investigated static and dynamic lattice properties in a quasi-one-dimensional charge-ordered semiconductor (NbSe4)3I by using Raman, femtosecond pump-probe spectroscopy and x-ray diffraction. In addition to a well-documented pseudo-Jahn-Teller ferrodistortive structural transition at TC=274 K, where the displacements of Nb ions lead to ferroelec...

We show that the specific heat of incommensurately modulated crystals with broken translational periodicity presents similar features at low temperatures to those of amorphous and glass materials. Here we demonstrate that the excess to the constant C p ðTÞ=T 3 law (or Debye limit) is made up of an upturn below 1 K and of a broad bump at T ≈ 10 K th...

We present the morphology and electrical conductivity of thin films of quasi one-dimensional conductor K0.3MoO3 produced by pulsed laser deposition. Atomic force microscopy reveals granular nature of the films with the texture depending on the substrate and deposition conditions. While the films with better texture have higher conductivity, they al...

We have measured the thermoelectric power of charge density wave system $o$-TaS$_{3}$ in a wide temperature range between 10 K and 300 K. All features characteristic for charge density wave systems have been observed; strong increase below charge density transition temperature $T_{P}$, peak at $T_{M}\sim$1/2-1/3 $T_{P}$ and change of sign at lower...

We report on the heat capacity investigation of Cu55Hf45−xTix metallic glasses. The most appropriate procedure to estimate low temperature electronic and phonon contributions has been determined. Both contributions exhibit monotonous Ti concentration dependence, demonstrating that there is no relation of either the electron density of states at the...

The Debye model predicts a T3 dependence of the specific heat Cp at sufficiently low tem- peratures in insulators and it reproduces a wealth of data in isotropic crystals. However, this simple and general law fails to account for the low temperature specific heat of amorphous compounds and this matter is currently the focus of many scientific activ...

Good understanding of how properties can be tuned by changing the size of material is a basic prerequisite for production of new materials with designed superior properties. Systems with charge density wave (COW) as a type of coupled electronic-lattice instability (usually found in low dimensional materials) are especially interesting due to their...

Good understanding of how properties can be tuned by changing the size of material is a basic prerequisite for production of new materials with designed superior properties. Systems with charge density wave (COW) as a type of coupled electronic-lattice instability (usually found in low dimensional materials) are especially interesting due to their...

An universal fingerprint of glasses has been found in low-temperature thermodynamic properties of charge/spin density wave (C/SDW) systems. Deviations from the well-known Debye, elastic continuum prediction for specific heat (flat Cp/T3 plot) appear as two anomalies; the upturn below 1 K and a broad bump at T∼10 K (named Boson peak in glasses). The...

Thin granular films of charge density wave (CDW) system K0.3MoO3 were prepared by pulsed laser deposition and investigated by various standard characterization methods such as GI-XRD, electric transport, TOF-ERDA, AFM and UV–visible spectroscopy. While all these methods indicate that the thin films consist of nanometer grains of K0.3MoO3, it is onl...

During the last years, femtosecond time-resolved spectroscopy (fsTRS) has become an important new tool to investigate low energy excitations in strongly correlated systems. By studying energy relaxation pathways linking various degrees of freedom (e.g., electrons, spin, or lattice), the interaction strengths between different subsystems can be dedu...

We have studied the dependence of the low electric field conductivity of the charge density wave (CDW) system o-TaS(3) on the temperature and applied electric field history. Without the application of high electric fields, the conductivity is higher on cooling than on heating in a wide temperature range below the CDW transition. With the applicatio...

Modulated charge or spin superstructures of organic quasi-one-dimensional conductors exhibit specific low-energy excitations (LEE) at very low temperatures due to metastable states caused by strong pinning centers. These phase excitations (soliton-like topological defects) demonstrate rich and unexpected properties in a magnetic field, due to their...

Forests cover approximately one fourth of the land's surface. As one of the largest oxygen sources in the nature, they are very important for the survival of life on Earth. Forest fires have become an increasingly interesting issue not only for forestry and ecology, which study them as an important phenomenon for the survival of forests themselves,...

We report measurements and data analysis of specific heat, susceptibility, and transport properties of Yb0.5Y0.5InCu4 in the temperature range between 2 and 300 K, and in magnetic fields of 0 and 5 T. The data can be consistently explained within the local-moment crystal-field theory with two close-lying doublets, Gamma6 and Gamma7 , in the ground...

Thirty years ago Fukuyama [J. Phys. Soc. Jpn. 45 (1978) 1474] predicted a transition from charge density wave (CDW) state to the charge density glass (CDG) at a finite temperature as the consequence of the competition between the uniform commensurability pinning and the random impurity pinning. We present strong evidence that the CDG phase indeed e...

We present the effects of the isoelectronic supstitution of Ta by (0.2 and 0.5 %) Nb atoms on the charge density wave (CDW) properties in o-TaS3. The characteristic, primary relaxation process which gives the maximum in the dielectric constant near 100 K disappears with slight doping. At the same time the minimum in threshold field in the same temp...

Here we report on detailed studies of the photoexcited carrier and collective mode dynamics in prototype quasi-1D charge density wave (CDW) systems K0.3MoO3K0.3MoO3 and Rb0.3MoO3Rb0.3MoO3 focusing on their low temperature and low excitation range. We show that the order parameter relaxation dynamics are inconsistent with the Rothwarf–Taylor model d...

Forests cover approximately one fourth of the land’s surface. As one of the largest oxygen sources in the nature, they are very important for the survival of life on Earth. Forest fires have become an increasingly interesting issue not only for forestry and ecology, which study them as an important phenomenon for the survival of forests themselves,...

The low frequency dielectric response of the charge density wave (CDW) system o-TaS3 exhibits a rate-independent hysteresis on temperature cycling in a very wide temperature range below the CDW transition temperature. The ac conductivity, related to the CDW dynamics, is higher on heating than on cooling, while the dc conductivity of residual free c...

Croatia is relatively rich in forests; forested areas account for 36 % of the total territory of the country. However, forest fires occurring in the Adriatic region of Croatia are a serious threat to natural resources, since they decrease biological diversity and exert a negative impact on landscape variety. The complexity of the problem requires t...

Thermally stimulated discharge current measurements were performed to study slow relaxation processes in two canonical charge density wave systems K(0.3)MoO(3) and o-TaS(3). Two relaxation processes were observed and characterized in each system, corroborating the results of dielectric spectroscopy. Our results are consistent with the scenario of t...

We prepared high-quality epitaxial thin films of charge density wave system Rb0.3MoO3 on MgO substrate. In continuation to the femtosecond spectroscopy performed in,1 new studies of femtosecond time-resolved Terahertz conductivity dynamics, necessary to directly probe the relaxation processes of photo-excited carriers, need high-quality thin films....

In the present work we reply to the Comment by Catalan and Scott (cond-mat/0607500) on two of our papers. This Comment has been rejected from publication in Physical Review Letters and, hence, our Reply is based on the cond-mat version.

The thermal conductivity of the charge-density-wave compound K0.3MoO3 has been investigated in the chain direction and in both perpendicular directions. A strong anisotropy is observed in the temperature range 100–300 K. The detailed analysis of the temperature dependence in all three directions confirms that in addition to the lattice and free car...

We report on broadband dielectric spectroscopy on the one-dimensional semiconductor (NbSe4)3I. Below the structural phase transition close to 270 K, which is accompanied by complex charge-order processes, we observe colossal dielectric constants with a frequency and temperature dependence very similar to what is observed in charge-density wave syst...

We report on the thermopower investigation of the pure orthorhombic TaS{3 }in temperature interval from 300 K down to 25 K and the doped one by Nb (Ta{0.995}Nb{0.005}S{3}) down to 80 K. Our results are in gross in agreement with the previously reported thermopower. However, we give an evidence of a change of slope at 150 K, before reaching a well d...

We have observed surprisingly huge dielectric response in a nominally semiconducting quasi one-dimensional system (NbSe{4})3I below structural phase transition at 274 K. While the relaxation time shows activated increase on cooling almost following the increase of dc resistivity, the dielectric constant goes through a maximum at 150 K. We discuss t...

We report on the effect of doping on the relaxational dynamics and the specific heat (C$_{\rm p})$ of the charge density wave (CDW) system o-TaS$_{3}$. Isoelectronic substitution of Ta atoms with 0.2%-0.5% of Nb suppresses the primary relaxation process responsible for the glass-like dielectric response of pure o-TaS$_{3}$ but only slightly affects...

We report on the temperature hysteresis observed in low frequency dielectric response and in nonlinear conductivity of charge density wave (CDW) system o-TaS$_{3}$. Between CDW transition temperature at 220 K and the glass transition temperature at 50 K both the amplitude and the relaxation time of the low frequency relaxational process are higher...

We present measurements of the dielectric response of quasi one-dimensional (TMTTF)2AsF6 in a wide temperature and frequency range. We provide a thorough characterization of the relaxational dynamics observed close to the ferroelectric-like transition at Tc = 100 K. Our measurements, extending up to 100 MHz, reveal a continuous slowing down of the...

We show that the low temperature (T < 0.5 K) time dependent nonexponential energy relaxation of quasi-one-dimensional compounds strongly differs according to the nature of their modulated ground state. For incommensurate ground states, such as in (TMTSF)(2)PF6 the relaxation time distribution is homogeneously shifted to larger time when the duratio...

Low-frequency dielectric spectroscopy and thermally stimulated discharge measurements of charge-density wave (CDW) system K0.3MoO3 are presented. Below 80 K two distinct relaxational processes are observed, which freeze at finite temperatures bearing close resemblance to the phenomenology of the dielectric response of glasses. We compare our result...

Low frequency dielectric spectroscopy and thermally stimulated discharge measurements of charge density wave (CDW) system K$_{0.3}$MoO$_{3}$ are presented. Below 80 K two distinct relaxational processes are observed, which freeze at finite temperatures bearing close resemblance to the phenomenology of the dielectric response of glasses. We compare...

Measurements of the magnetic susceptibility and its anisotropy in the quasi one-dimensional system o-TaS3 in its low-T charge-density-wave (CDW) ground state are reported. Both sets of data reveal below 40 K an extra paramagnetic contribution obeying a power law temperature dependence chi(T) = AT-0.7. The fact that the extra term measured previousl...

We report on a study of the slow dynamics of the heat relaxation at very low temperature (T less than or equal to 1 K) in the nominally commensurate ground states of the sulfide compounds (TMTTF)(2)Br and (TMTTF)(2)PF6, commensurate SDW - or antiferromagnetic - and spin-Peierls, respectively. For both systems, the long-time dynamics at equilibrium...

We present experimental evidence for the glass transition in charge density wave (CDW) superstructure of two quasi one-dimensional systems, o-TaS3 and K0.3MoO3. Low frequency dielectric response of both systems exhibits typical glass-like phenomenology, featuring the splitting of the relaxational spectrum into two processes on decreasing the temper...

We report on the power-law dependence on temperature of the magnetic susceptibility and the specific heat of the CDW (charge density wave) system o-TaS3. All the evidences are in favor of a typical REHAC (random exchange Heisenberg antiferromagnetic chain) behaviour [1], however in the diluted limit of spins s=1/2. We propose a consistent microscop...

We compare the electric field and frequency dependence of the complex shear moduli of the charge-density-wave (CDW) conductors, TaS3 and NbSe3. For both materials, the magnitudes of the shear moduli decrease when the CDW becomes depinned, but qualitatively different behaviors are observed for their internal friction. For TaS3, the frequency depende...

Low frequency dielectric response of charge density wave systems K0.3MoO3 and o-TaS3 shows hysteresis on temperature cycling. The closing of the hysteresis at low temperature coincides in both systems with the closing of the hysteresis in DC conductivity and corresponds to the temperature of the glass transition observed in dielectric response of t...

This contribution is in continuation of our preceding publication (Lasjaunias J C, Brison J P, Monceau P, Staresinic D, Biljakovic K, Carcel C and Fabre J M 2002 J. Phys.: Condens. Matter 14 837) in which we have considered general aspects of the low-temperature thermodynamical properties of the quasi-one-dimensional organic salts based on sulphur...

Specific heats of the charge-density-wave compounds o-TaS3 and (TaSe4)2I have been measured over the wide temperature interval 10 K-300 K. Both systems exhibit strong non-Debye behavior. Very weak and broad anomalies are observed at the Peierls transition temperatures. For o-TaS3, the change in the curvature of the specific heat occurs at temperatu...

Eur. Phys. J. B 24, 315 (2001) In our Reply to the Comment [#!1!#] we refute the “straightforward” interpretation of the excess low-temperature specific heat, Cp, contribution we have measured in our study of CDW systems K0.3MoO3 and (TaSe4)2I [#!2!#] as originating solely from normal phonon modes. The specific sensitivity of the bump in C p / T 3...

We present a detailed investigation of the low-frequency dielectric response of the charge-density-wave system (CDW) o-TaS3 in wide temperature (5–300 K) and frequency (10 mHz to 100 MHz) ranges. Although our measurements agree relatively well with data performed in some restricted frequency and temperature ranges and previously published by severa...

We report on measurements of the electric field dependence of the complex shear compliance of the charge-density-wave (CDW) conductor NbSe_3, for torsional frequencies between 1 Hz and 71 Hz. For one sample, the magnitude of the compliance increases (by ~ 1%) when the field exceeds the threshold for CDW depinning and its phase shift (i.e. the inter...

A detailed thermodynamical investigation of the quasi-one-dimensional sulphur-based organic salts (TMTTF)2PF6 and (TMTTF)2Br is presented in the temperature range from 30 mK to 7 K. In this part (part I), we consider the general aspects of the low-temperature specific heat of these materials in relationship with their ground states and we compare t...

Specific heats of the charge-density-wave compounds and (TaSe{4}){2}I have been measured over the wide temperature interval 10 K 300 K. Both systems exhibit strong non-Debye behavior. Very weak and broad anomalies are observed at the Peierls transition temperatures. For , the change in the curvature of the specific heat occurs at temperature of 40...

Accumulated experimental evidence points to the change of the properties of charge and spin density wave (CDW/SDW) systems below a temperature T*&ap;1/3-1/4 TP (where T_P= the Peierls transition temperature). Studies of the low frequency dielectric response and the thermal capacity of a few CDW systems strongly indicates that this change is due to...

We report on the specific heat of the charge-density-wave (CDW) materials (TaSe_4)_2I and TaS3 measured at temperatures between 5 K and 300 K using pulsed calorimetry. An extended scaling analysis reveals two features for each material that are not obvious in plots of the specific heat vs. temperature. The first are small cusps at the Peierls trans...

We report on measurements of the voltage dependence of the complex shear compliance of two crystals of the charge-density-wave (CDW) conductor NbSe3, for torsional frequencies between 1 Hz and 71 Hz. For both samples, there is a frequency independent, ∼1% increase of the magnitude of the compliance when the voltage exceeds the threshold for CDW dep...

We report the temperature evolution of the low-frequency (f<10 MHz) dielectric response of the CDW material orthorombic TaS3 between 150 K and 10 K. Ther-e are two distinctive processes observed bellow and above 50 K that define different ground states of CDW. The first one due to the weakly pinned elastic CDW freezes at about 50 K and a second one...

We present a study of the slow dynamics in the heat relaxation at very low temperature (T < 1 K) in the nominally commensurate SDW compound (TMTTF)2Br, that we compare to the incommensurate SDW-(TMTSF)2PF6. Instead of a broad distribution of relaxation times g(log r) in the PF6 salt, the dynamics in the Br salt reveals almost "discrete bands" in th...

We have investigated dynamics of various CDW compounds in the low temperature insulating highly polarisable state by means of thermally stimulated discharging. Current spectra are observed in the temperature range where the response time of the CDW exceeds seconds. Special attention is given to the o-TaS3 that shows the most complex behavior.

We report on the experimental evidence of a glass transition in the CDW phase of orthorhombic TaS3 at Tg ~ 50 K, brought by means of dielectric constant measurement. The relaxational mode exhibits in this T-range a critical slowing down instead of an expected activated behavior. New processes appear below the glass transition temperature which we a...

We report on specific heat measurements of the quasi-one-dimensional organic salt (TMTSF)2AsF6 in its spin density wave state between 75 mK and 7 K. Similarly to (TMTSF)2PF6, we find discontinuities in the lattice contribution at 1.9 K an d 3.5 K ascribed to sub-spin density wave phases. Time-dependent effects due to dynamics of low-energy excitati...

We report measurements of thermal conductivity in the 30 - 350 K range of hard fullerene-based carbon. The material has been prepared by pressure - temperature treatment of fullerene. It shows an unusual combination of high hardness and relatively high electrical conductivity. Its thermal conductivity is about at room temperature and decreases almo...

We report the temperature evolution of the low-frequency (f<10 MHz) dielectric response of the CDW material orthorombic TaS3 between 150 K and 10 K. There are two distinctive processes observed bellow and above 50 K that define different ground states of CDW. The first one due to the weakly pinned elastic CDW freezes at about 50 K and a second one...

We have found by broad-band dielectric spectroscopy of charge density wave (CDW) compound TaS3 that the main relaxation time representing CDW viscosity shows a critical slowing down in the range 55-50 K. At lower temperatures two additional processes appear that we assign to the defects in CDW superlattice. Based on very strong similarity with the...

Wê report on the first thermodynamical investigation of (TMTTF)2Br in its antiferromagnetic ground state. There is a discontinuity in the lattice specific heat, CP/T3, at 1.9-2.0 K which seems to reflect the existence of the Spin Density Wave (SOW) sub-phase. This discontinuity is similar to those we have measured in other quasi one-dimensional org...

We report measurements of thermal conductivity in 30–350 K range of hard fullerene-based carbon. The material has been prepared from C60 fullerene under pressure and has an unusual combination of large hardness and relatively high electrical conductivity. Its thermal conductivity is about 5.5 W/mk at room temperature and decreases almost linearly i...

We present the investigation of low-energy excitations in CDW compounds by means of ultra low-frequency dielectric spectroscopy. The method of thermally stimulated discharging current (TSDC) with effective frequencies in the range 10-10 Hz has been used in addition to the measurement of transient current recorded in seven decades of time. These met...