Related papers: Bose-Einstein Condensation of Triplons in Ba3Cr2O8
Heat capacity and magnetic torque measurements are used to probe the anisotropic temperature-field phase diagram of the frustrated spin dimer compound Ba3Mn2O8 in the field range from 0T to 18T. For fields oriented along the c axis a single…
Bose-Einstein condensation (BEC) of an ideal gas is investigated, beyond the thermodynamic limit, for a finite number $N$ of particles trapped in a generic three-dimensional power-law potential. We derive an analytical expression for the…
The miscibility condition for a binary mixture of two interacting Bose-Einstein condensates is shown to be deeply affected by interaction driven thermal fluctuations. These give rise to a first order phase transition to a demixed phase with…
We discuss the occurrence of Bose-Einstein condensation in systems of noninteracting charged particles in three in one dimensions and in presence of an external magnetic field. In the one dimensional, as well as in the magnetic field cases,…
To study the relationship between the properties of low-dimensional spin systems with weakly coupled Cu-triangles and their crystal structure, single crystals of $Cs_3Cu_3Cl_8OH$ (1) and the new $Cs_3Cu_3Cl_{7.6}Br_{0.4}OH$ (2) were grown.…
Specific heat measurements have been performed in the coupled dimer system TlCuCl$_3$, which has a singlet ground state with the excitation gap $\Delta \simeq 7.5$K. The cusplike anomaly indicative of the 3D magnetic ordering was clearly…
We studied phase transitions and thermodynamic properties of the field-induced antiferromagnetic nuclear-spin ordered phase in bcc solid 3He by measuring the melting pressure at temperatures down to 0.4 mK in magnetic fields up to 15 T. The…
Traditionally, when one describes the crystallographic structure of oxides, the oxygen ion radius r02 is assumed to be approximately equal to 1.4A. The oxygen ions occupy in this case 80-90% of the crystal volume. Metal atoms are considered…
K$_2$CuF$_4$ is magnetically described as a spin-1/2, quasi-two-dimensional (2D), square-lattice XXZ ferromagnet with weak easy-plane anisotropy. The magnetic ordering for an applied magnetic field $H$ parallel to the $c$ axis is equivalent…
We address the problem of identifying the critical temperature in a crossover from the Bose-Einstein condensed (BEC) phase to the normal phase. For this purpose we study the temperature dependence of magnetization of spin-gapped quantum…
We have measured the thermal conductivity of a TlCuCl$_3$ single crystal in magnetic fields up to 14 T. It has been found that the temperature dependence of the thermal conductivity exhibits a sharp peak at 4 K in zero field, which is…
We study the spin dynamics in the quasi-2D spin-$1/2$ dimer compound Ba$_2$CuSi$_2$O$_6$Cl$_2$, which exhibits a magnetic field-induced Bose-Einstein condensate (BEC) of triplons. Using nuclear magnetic resonance (NMR) spin-lattice…
We compute the shift of the transition temperature for a homogenous weakly interacting Bose gas in leading order in the scattering length a for given particle density n. Using variational perturbation theory through six loops in a classical…
High-field magnetic torque measurements were carried out in the spin gap system (CH$_3$)$_2$CHNH$_3$CuCl$_3$. It was observed that the magnitude of the magnetic torque $\tau$ is almost zero until the critical field and then increases…
Bose-Einstein condensation of electron-hole pairs, exciton condensation, has been effortfully investigated since predicted 60 years ago. Irrefutable evidence has still been lacking due to experimental difficulties in verifying the…
The shift of the Bose-Einstein condensation temperature for a homogenous weakly interacting Bose gas in leading order in the scattering length `a' is computed for given particle density `n.' Variational perturbation theory is used to resum…
It is investigated theoretically that magnetized Bose-Einstein condensation (BEC) with the internal (spin) degrees of freedom exhibits a rich variety of phase transitions, depending on the sign of the interaction in the spin channel. In the…
We calculate explicitly the variation $\delta T_c$ of the Bose-Einstein condensation temperature $T_c$ induced by weak repulsive two-body interactions to leading order in the interaction strength. As shown earlier by general arguments,…
Thermodynamics of spin dimer system BaCuSi_2O_6 is studied using a quantum Monte Carlo calculation (QMC) and a bond-operator mean field theory. We propose that a new type of boson, which, rather than being hard-core, allows up to two…
We present magnetic characterization of a binary rare-earth intermetallic compound Er5Si3, crystallizing in Mn5Si3-type hexagonal structure, through magnetization, heat-capacity, electrical resistivity, and magnetoresistance measurements.…