Magnetic phase transitions in triangular-lattice antiferromagnetic mixed crystals CsNi0.98M0.02Cl3 (M=Co, Fe, Mg)

Large easy-plane anisotropy induced spin reorientation in magnetoelectric materials (Co4−x Mn x )Nb2O9

“…Actually, a similar doping effect has been reported in CsNiCl 3 with P6 3 /mmc space group. CsNiCl 3 was reported to have very special magnetic structure with an Ising-like anisotropy, namely, easy-axis anisotropy [24][25][26]. By doping with only 0.7 at% Fe on Ni sites, this magnet changes into an in-plane (XY) magnetic structure [24][25][26][27].…”

“…CsNiCl 3 was reported to have very special magnetic structure with an Ising-like anisotropy, namely, easy-axis anisotropy [24][25][26]. By doping with only 0.7 at% Fe on Ni sites, this magnet changes into an in-plane (XY) magnetic structure [24][25][26][27]. The researchers ascribed such a very strong doping effect to the high easy-plane single-ion anisotropy of Fe 3+ in this crystal structure, compared to the weak easy-axis anisotropy of Ni 2+ [27].…”

Review/Synthèse: Triangular antiferromagnets

“…For example, in pure RbNiCl 3 the splitting between T N 1 and T N 2 is very small, 0.14 T [110], while addition of only 5% of Co results in as much as 9 K between T N 1 and T N 2 [279]. Magnetic phase diagrams of Heisenberg triangular antiferromagnet, CsNi 0.98 M 0.02 Cl 3 (M =Co, Fe, Mg) have been determined by heat capacity [280] and ultrasonic velocity [281] measurements. As expected, when comparing with pure CsNiCl 3 , the Co-doped crystal shows enhanced Ising effective single-ion anisotropy -the spin-flop field H SF and the splitting between T N 1 and T N 2 are sufficiently increased; the Fe-doped crystal behaves as a Heisenberg antiferromagnet with XY type of anisotropy -the phase diagram is very similar to those in CsMnBr 3 ; in the Mg-doped crystal nonmagnetic impurity causes decrease of effective single-ion anisotropy and values of H SF and T N consequently.…”