Magnetocaloric effect in the distorted Ising-Heisenberg double sawtooth spin ladders
Abstract
The entropy and cooling rate of the both antiferromagnetic spin-1/2 double sawtooth IsingHeisenberg model and mixed-spin (1,1/2) double sawtooth Ising-Heisenberg model on the distorted ladders are rigorously investigated under an adiabatic demagnetization process using the quantum transfer-matrix technique. The models include the XXZ interaction between the interstitial Heisenberg dimers, the Ising coupling between nearest-neighbor spins of the legs and rungs, and additional cyclic four-spin exchange (ring exchange) in the square plaquette of each block. Close to field-induced quantum phase transitions, we compare both models together in the ability of cooling/heating near the quantum critical points. However, we observe a large magnetocaloric effect for both models, the mixed-spin double sawtooth ladder shows much more magneticaloric efficiency than the spin-1/2 double sawtooth ladder. During an adiabatic demagnetization process it can be seen a temperature dropping in the vicinity of the zero-temperature quantum phase transitions. Various fixed values of the Isotropic and anisotropic parameters explicitly alter the quality of the magnetocaloric effect. This properties suggest double sawtooth Ising-Heisenberg ladders as promising alternative refrigerant materials for low-temperature magnetic refrigeration.
Keywords
Cite
@article{arxiv.1805.05607,
title = {Magnetocaloric effect in the distorted Ising-Heisenberg double sawtooth spin ladders},
author = {Hamid Arian Zad and Vadim Ohanyan},
journal= {arXiv preprint arXiv:1805.05607},
year = {2018}
}
Comments
Unfortunately, we found some mistakes and typos. For instance: 1. The considered model is NOT INTEGRABLE as we mentioned in the text This is a wrong statement. 2. the method we use in the paper is not a QUANTUM transfer matrix method. We have just a classical transfer-matrix. 3. The object we call a "permutation operator" is not permutation operator