Magnetization process of the breathing pyrochlore magnet CuInCr4S8 in ultrahigh magnetic fields up to 150 T

Abstract

The magnetization process of the breathing pyrochlore magnet CuInCr 4 S 8 has been investigated in ultra-high magnetic fields up to 150 T. Successive phase transitions characterized with a substantially wide 1/2-plateau from 55 T to 110 T are observed in this system, resembling those reported in chromium spinel oxides. In addition to the 1/2-plateau phase, the magnetization is found to exhibit two inherent behaviors: a slight change in the slope of the M-H curve at ∼ 85 T and a shoulder-like shape at ∼ 130 T prior to the saturation. Both of them are accompanied by a hysteresis, suggesting first-order transitions. The theoretical calculation applicable to CuInCr 4 S 8 is also shown, based on the microscopic model with the spin-lattice coupling. The calculation fairly well reproduces the main features of the experimentally observed magnetization process, including a relatively wide cant 2:1:1 phase clearly observed in the previous work [Y. Okamoto et al., J. Phys. Soc. Jpn. 87, 034709 (2018)]. The robust 1/2-plateau on CuInCr 4 S 8 seems to be originated from the dominant antiferromagnetic interactions and the strong spin-lattice coupling.

Spin ordering induced by lattice distortions in classical Heisenberg antiferromagnets on the breathing pyrochlore lattice

“…In experiments, although various classes of breathing pyrochlore antiferromagnets such as the chromium oxides Li(Ga, In)Cr 4 O 8 [53, 59-66, 69, 70] and sulfides Li(Ga, In)Cr 4 S 8 [67,68,71] and the quantum magnet Ba 3 Yb 2 Zn 5 O 11 [72][73][74][75][76] have been studied, the ( 1 2 , 1 2 , 1 2 ) spin correlation has not been reported so far. On the other hand, the uniform pyrochlore antiferromagnets GeB 2 O 4 (B=Ni, Co, Fe, Cu) [77][78][79][80][81][82][83][84][85][86][87] do exhibit ( 1 2 , 1 2 , 1 2 ) magnetic LRO, although the experimentally proposed spin structure as well as the estimated exchange interactions (e.g., ferromagnetic J 1 ) seems to be different from the ones in the present theoretical model.…”

Hierarchical excitations from correlated spin tetrahedra on the breathing pyrochlore lattice

“…The corresponding exclusive structure factor S zz can be calculated as: units integrated in the energy range of [2,6] meV for the Ei = 50 meV spectra (a) and [15,25] meV for the Ei = 100 meV spectra. Error bars representing the standard deviations are smaller than the marker size.…”

“…Further complications could arise from spin-lattice coupling that is often observed in the Cr-based spinels [16,24]. Recent high-field measurements on CuInCr 4 S 8 revealed a halfmagnetization plateau that is reminiscent of a similar feature observed in ZnCr 2 O 4 , indicating the existence of biquadratic interactions that could arise from spin-lattice coupling [22,[25][26][27].…”

“…Along with interactions neglected in our minimal model, the coupling to the lattice DOF could produce extra modes that is beyond a spin-only description. Additionally, the recent high-field magnetization measurements [22,25] demonstrate that the spin-lattice coupling in CuInCr 4 S 8 induces effective biquadratic interactions, which provide a possible explanation of the negative Θ CW as biquadradratic interactions are known to enhance the Heisenberg (billinear) interactions between the FM spins without affecting Θ CW [38,39]. Therefore, the strong FM J 1 in CuInCr 4 S 8 may receive a considerable enhancement through the coupling to the lattice DOF.…”

Synthesis, physical and magnetic properties of CuAlCr$_4$S$_8$: a new Cr-based breathing pyrochlore

“…This occurs by displacement of the octahedral Bsite cation and ordering of X anions [8]. Numerous mixed A-site pyrochlores have been synthesized in the past with some examples of the A-site ordering [9][10][11][12][13][14][15][16][17][18]. Since the type of interaction between nearest neighbor chromium atoms is distance sensitive, changing from strongly antiferromagnetic in oxide spinel to ferromagentic in selenium spinel [19], the magnetic Cr +3 atoms at the edges of larger and smaller tetrahedra have different interaction * luke@mcmaster.ca x-ray diffraction data taken at 300 K and 12 K. There is a small shift in the intensities and peak positions between the two temperatures, but no different peaks occur at the different temperatures.…”