Long-range antiferromagnetic order and possible field induced spin-flop transition in BiMnVO5.
We report the bulk magnetic characterization of a dimeric chain material, BiMnVO5, by means of magnetic susceptibility, magnetization and heat capacity measurements. Our results provide compelling evidence of an antiferromagnetic (AFM) transition at (TN) ~ 11.5 K. Moreover, the magnetic entropy change in zero field saturates to 14.6 J mol-1K-1which is close to the total spin entropy of Mn2+. The development of long-range magnetic order in this chain material demonstrates the interplay of strong intra-chain and inter-chain interactions between the dimers, in addition to the intra-dimer interaction. Low-temperature (T  <  TN) heat capacity data indicate the presence of a gap (Δ/kB≈  5 K) in the spin excitations. Furthermore, the isothermal magnetization below TNshows an anomaly in the slope between 30 and 40 kOe which is suggestive of a spin-flop transition. Such a low-field spin-flop transition and gapped spin wave excitations may be attributed to the presence of (weak) magnetic anisotropy in this material. We attempt to construct a phase diagram in the magnetic field-temperature plane by extracting data from in-field heat capacity and isothermal magnetization measurements.
School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 751007, India.
S
S
Chowki
R
R
Kumar
N
N
Mohapatra
A V
AV
Mahajan