Magnetic phase diagrams, domain switching, and quantum phase transition of the quasi-one-dimensional Ising-like antiferromagnet BaCo2V2O8

Abstract

In the effective Ising spin-1/2 antiferromagnetic chain system BaCo2V2O8, the magnetic-field influence is highly anisotropic. For magnetic fields along the easy axis c, the Néel order is strongly suppressed already for low fields and an incommensurate order is entered above 4 T. We present a detailed study of the magnetic phase diagrams for different magnetic field directions, which are derived from magnetization data, high-resolution thermal expansion and magnetostriction measurements as well as from the thermal conductivity. Zero-field thermal expansion data reveal that the magnetic transition is accompanied by an orthorhombic distortion within the ab plane. Under ambient conditions the crystals are heavily twinned, but the domain orientation can be influenced either by applying uniaxial pressure or a magnetic field along the [100] direction. In addition, our data reveal a pronounced in-plane magnetic anisotropy for fields applied within the ab plane. For H [110], the magnetic field influence on TN is weak, whereas for magnetic fields applied along [100], TN vanishes at about 10 T and the zero-field Néel order is completely suppressed as is confirmed by neutron diffraction data. The second-order phase transition strongly suggests a quantum critical point being present at H 10 T parallel [100], where the Néel order probably changes to a spin-liquid state. The magnetization has been measured in a vibrating sample magnetometer (PPMS, Quantum Design) for temperatures above 2 K up to a maximum magnetic

Quantum Criticality of an Ising-like Spin- 1/2 Antiferromagnetic Chain in a Transverse Magnetic Field

“…With increasing field up to 15 T, the ordering phase boundary shifts moderately to lower temperatures, as reflected by the ∆v(T )/v curves [ Fig. 2(b)], in agreement with the thermal-expansion measurements [36]. Figure 3 shows the magnetization and sound velocity as a function of magnetic field up to 60 T for various temperatures.…”

“…Even in high magnetic fields, this effective model provides a valid description, since the Zeeman interaction is sufficiently small compared with the spin-orbit coupling [40][41][42]. The local Ising axes are slightly tilted from the c axis reflecting the fourfold screw-axis symmetry, which leads to an additional but weaker in-plane anisotropy [36,40,43,44]. In zero field, a 3D long-range antiferromagnetic order is stabilized at T N ∼ 5 K by weak inter-chain couplings [34,36].…”

“…Figure 2(a) shows the magnetization for a transverse field of 1 T as a function of temperature. With decreasing temperature, the magnetization increases and exhibits a sudden drop with a maximum slope at T N , signaling the phase transition to the antiferromagnetic phase [36]. At the phase transition, the sound velocity ∆v(T )/v in zero field exhibits a sharp softening [ Fig.…”

Field-Induced Magnonic Liquid in the 3D Spin-Dimerized AntiferromagnetSr3Cr2O8Wang1, Quintero-Castro2, Жерлицын3 et al. 2016Phys. Rev. Lett.192801View full textAdd to dashboardCite

“…1(f)] 22 , which with spin S = +1 or −1 can be split in longitudinal magnetic field and exhibit linear field dependence 20,22 . By applying a transverse magnetic field, the Néel temperature can be reduced according to the magnetic susceptibility measurements 26,27,[30][31][32] . At 2 K, a phase transition from the Néel antiferromagnetic (AFM) phase to a disordered paramagnetic (PM) phase is induced by a transverse field of 7 T 26,27 .…”

Giant magnetic field dependence of the coupling between spin chains inBaCo2V2O8

“…Among them, BaCo 2 V 2 O 8 [27] has been recently studied [28][29][30][31][32][33][34][35][36][37][38][39][40][41] as one of a few with accessible critical fields, i.e., B c = 3.8 T and B s = 22.8 T [30]. The system develops a standard low-temperature Néel ordered phase in the field range up to B c [29,31] (Fig.…”