Continuous control of classical-quantum crossover by external high pressure in the coupled chain compound CsCuCl3

Abstract

In solid materials, the parameters relevant to quantum effects, such as the spin quantum number, are basically determined and fixed at the chemical synthesis, which makes it challenging to control the amount of quantum correlations. We propose and demonstrate a method for active control of the classical-quantum crossover in magnetic insulators by applying external pressure. As a concrete example, we perform high-field, high-pressure measurements on CsCuCl3, which has the structure of weakly-coupled spin chains. The magnetization process experiences a continuous evolution from the semi-classical realm to the highly-quantum regime with increasing pressure. Based on the idea of "squashing” the spin chains onto a plane, we characterize the change in the quantum correlations by the change in the value of the local spin quantum number of an effective two-dimensional model. This opens a way to access the tunable classical-quantum crossover of two-dimensional spin systems by using alternative systems of coupled-chain compounds.

Magnetic-field and pressure phase diagram of the triangular lattice antiferromagnet CsCuCl$_3$ clarified by magnetic susceptibility measured with a proximity detector oscillator

“…(b).The pressure dependences of H c1 /H sat and H c2 /H sat qualitatively agree with the calculation[32], and similar results were obtained by Yamamoto et al[33]. The emergence of the Y coplanar phase was expected at ∆ ≤ 0.05 and H c1 /H sat ≤ 0.3, as shown in Fig.6 (b).…”

“…We succeeded in measuring the shift of the PDO frequency that corresponds to the field derivation of magnetization over the saturation field, and clarified the pressure dependence of J 0 and ∆. The magnetic field versus pressure phase diagram of CsCuCl 3 constructed from the experimental results agrees qualitatively with that obtained by theoretical calculations [32,33].The anomaly just below the saturation field for H c at 1.4 -4.2 K was observed in the PDO measurements and not in the conventional magnetization measurements. This anomaly may correspond to the transition field caused by the nonlinear AC magnetic response in PDO measurements.…”

“…Therefore, the pressure dependence of J 1 did not change much in both cases of J 0 /k B = constant and J 0 /k B = 28.45 -10.49P reported in Ref. [33] . The magneticfield normalized by the H sat versus pressure phase diagram of CsCuCl 3 is shown in Fig.…”

“…GPa in magnetic fields of up to 5 T [33]. In both theories, the change in the ratio of J 0 to J 1 was important for the appearance of the field-and pressure-induced magnetic phases.…”

Collinear antiferromagnetic order in spin-$\frac52$ triangle lattice antiferromagnet Na$_3$Fe(PO$_4$)$_2$

“…Recently, an extended fluctuating regime with slow dynamics below magnetic ordering is detected in the spin-3/2 isotropic TLAs [23]. Overall, diverse phase regimes are anticipated in TLAs while going from a classical (high spin) to quantum (low spin) limit owing to the geometrical frustration in concurrence with magnetic anisotropy, effect of fluctuations * rnath@iisertvm.ac.in etc [24,25].…”