相关论文: Magnetostriction in the Bose-Einstein Condensate q…
It has recently been suggested that the organic compound NiCl$_2$-4SC(NH$_2$)$_2$ (DTN) exhibits Bose-Einstein Condensation (BEC) of the Ni spin degrees of freedom for fields applied along the tetragonal c-axis. The Ni spins exhibit 3D…
At zero temperature and strong applied magnetic fields the ground sate of an anisotropic antiferromagnet is a saturated paramagnet with fully aligned spins. We study the quantum phase transition as the field is reduced below an upper…
In this work, we demonstrate field-induced Bose-Einstein condensation (BEC) in the organic compound NiCl$_2$-4SC(NH$_2$)$_2$ using AC susceptibility measurements down to 1 mK. The Ni $\textsl{S}$=1 spins exhibit 3D $\mathit{XY}$…
Quantum magnets offer a unique platform for exploring exotic quantum phases and quantum phase transitions through external magnetic fields. A prominent example is the field-induced Bose--Einstein condensation (BEC) of magnons near the…
A Bose-Einstein condensation (BEC) has been observed in magnetic insulators in the last decade. The bosons that condensed are magnons, associated with an ordered magnetic phase induced by a magnetic field. We review the experiments in the…
Three hyperfine states of Bose-condensed sodium atoms, recently optically trapped, can be described as a spin-1 Bose gas. We study the behaviour of this system in a magnetic field, and construct the phase diagram, where the temperature of…
Building on recent NMR experiments [Phys. Rev. Lett. 118, 067203], we theoretically investigate the high magnetic field regime of the disordered quasi-one-dimensional $S=1$ antiferromagnetic material…
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 report on results of specific heat measurements on single crystals of the frustrated quasi-2D spin-1/2 antiferromagnet Cs_2CuCl_4 (T_N=0.595 K) in external magnetic fields B<12 T and for temperatures T>30 mK. Decreasing B from high…
Combined experimental and modeling studies of the magnetocaloric effect, ultrasound, and magnetostriction were performed on single-crystal samples of the spin-dimer system Sr$_3$Cr$_2$O$_8$ in large magnetic fields, to probe the…
$Ni Cl_2$-$4SC(NH_2)_2$ (known as DTN) is a spin-1 material with a strong single-ion anisotropy that is regarded as a new candidate for Bose-Einstein condensation (BEC) of spin degrees of freedom. We present a systematic study of the…
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…
An asymmetric Bose-Einstein condensation (BEC) dome was observed in a recent experiment on the quantum dimer magnet $\rm Yb_2Si_2O_7$, which is modeled by a "breathing" honeycomb lattice Heisenberg model with possible anisotropies. We…
Spinor Bose-Einstein condensates under external magnetic fields exhibit well-characterized spin domains of its ground state due to spin-dependent interactions. At low temperatures, collision-induced spin-mixing instabilities may promote the…
Based on a realistic spin Hamiltonian for a frustrated quasi-two dimensional spin-1/2 antiferromagnet Cs$_{2}$CuCl$_{4}$, a three-dimensional spin ordering in the applied magnetic field $B$ near the saturation value $B_{c}$ is studied…
The spin-1 anisotropic antiferromagnet NiCl_2-4SC(NH2)_2 exhibits a field-induced quantum phase transition that is formally analogous to Bose-Einstein condensation. Here we present results of systematic high-field electron spin resonance…
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,…
Bose-Einstein condensation (BEC) of triplet excitations triggered by a magnetic field, sometimes called magnon BEC, in dimerized antiferromagnets gives rise to a long-range antiferromagnetic order in the plane perpendicular to the applied…
Nuclear magnetic resonance (NMR) study of the high magnetic field (H) part of the Bose-Einstein condensed (BEC) phase of the quasi-onedimensional (quasi-1D) antiferromagnetic quantum spin-chain compound NiCl2-4SC(NH2)2 (DTN) was performed.…
We study the thermodynamic properties of a non-interacting, relativistic gas of charged scalar bosons in a uniform magnetic field, including both statistical and vacuum contributions at arbitrary field strengths. Focusing on the…