Related papers: Multiferroic quantum criticality in (Eu,Ba,Sr)TiO$…
Magnetic dc susceptibility between 1.5 and 800 K, ac susceptibility and magnetization, thermodynamic properties, temperature dependence of radio and audio-wave dielectric constants and conductivity, contact-free dielectric constants at…
We present a thorough $^{77}$Se NMR study of a single crystal of the magnetoelectric compound Cu$_2$OSeO$_3$. The temperature dependence of the local electronic moments extracted from the NMR data is fully consistent with a magnetic phase…
Using high-precision numerical analysis, we show that 3+1 dimensional gauge theories holographically dual to 4+1 dimensional Einstein-Maxwell-Chern-Simons theory undergo a quantum phase transition in the presence of a finite charge density…
The quantum tricriticality of d-dimensional transverse Ising-like systems is studied by means of a perturbative renormalization group approach focusing on static susceptibility. This allows us to obtain the phase diagram for 3<d<4, with a…
Dielectric spectroscopy of $SrTiO_3$ single crystal over a broad range of microwave frequency using quasi $TE_{m,1,1}$ and quasi $TM_{m,1,1}$ modes reveals crystal asymmetry from typical measurement of $Q$-factor, transmission or frequency…
The structural phase transition in hexagonal BaMnO$_3$ occurring at $T_c$=130 K was studied in ceramic samples using electron and X-ray diffraction, second harmonic generation as well as by dielectric and lattice dynamic spectroscopies. The…
We report on susceptibility measurements in the strongly correlated layered cobalt oxide [BiBa0.66K0.36O2]CoO2, which demonstrate the existence of a magnetic quantum critical point (QCP) governing the electronic properties. The investigated…
The electrical transport and thermoelectric properties of K_xSr_{1-x}Fe_2As_2 are investigated for 0<x<1. The resistivity rho(T) shows a crossover from Fermi liquid-like temperature dependence at small x to linear rho~T dependence at…
We study the temperature dependence of the conductivity due to quantum interference processes for a two-dimensional disordered itinerant electron system close to a ferromagnetic quantum critical point. Near the quantum critical point, the…
Phase transition between ferroelectricity and quantum paraelectricity via non-thermal tuning parameters can lead to quantum critical behavior and associated emergent phenomena. Ferroelectric quantum critical systems are, however, rare…
SrTiO$_{3}$ undergoes a cubic-to-tetragonal phase transition at 105K. This antiferrodistortive transition is believed to be in competition with incipient ferroelectricity. Substituting strontium by isovalent calcium induces a ferroelectric…
To explore the possibility of quantum phase transitions and even quantum criticality in LaCrSb$_3$ based compounds, we performed measurements under pressure as well as a vanadium substitution study. The Curie temperature of LaCrSb$_3$ was…
Cu3Nb2O8 is an unusual multiferroic compound that undergoes a series of magnetic ordering at low temperatures. Concurrent development of electric polarization has been reported at TN1 ~25 K corresponding to a non-collinear helicoidal…
Nearly magnetic metals often have layered lattice structures, consisting of coupled planes. In such a situation, physical properties will display, upon decreasing temperature or energy, a dimensional crossover from two-dimensional (2d) to…
Quasi-two dimensional itinerant fermions in the Anti-Ferro-Magnetic (AFM) quantum-critical region of their phase diagram, such as in the Fe-based superconductors or in some of the heavy-fermion compounds, exhibit a resistivity varying…
We report results of a comprehensive study of the phase transition at T_N (~643 K) as a function of particle size in multiferroic BiFeO3 system. We employed electrical, thermal, and temperature dependent X-ray diffraction (XRD) studies in…
We propose a phenomenological spin fluctuation theory for antiferromagnetic quantum tricritical point (QTCP), where the first-order phase transition changes into the continuous one at zero temperature. Under magnetic fields, ferromagnetic…
Our measured dielectric constant and mechanical response of multiferroic BiFeO3 indicate four phase transitions below room temperature. Features correlate with those reported at 50K (from a peak in the zero-field-cooled magnetic…
Resistivity under pressure and magnetization measurements on Ba$_{1-x}$Sr$_x$VS$_3$ single crystals with 0 $\leq x \leq$ 0.18 and no sulphur deficiency show an abrupt onset of ferromagnetic (FM) order at a critical value $x$=0.07,…
Metallic quantum criticality is frequently discussed as a source for non-Fermi liquid behavior, but controlled theoretical treatments are scarce. Here we identify and study a novel magnetic quantum critical point in a two-dimensional…