Significant inverse magnetocaloric effect induced by quantum criticality,Physical Review Research

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Significant inverse magnetocaloric effect induced by quantum criticality
Physical Review Research ( IF 3.5 ) Pub Date : 2021-07-27 , DOI: 10.1103/physrevresearch.3.033094
Tao Liu _{1,

2} , Xin-Yang Liu ₂ , Yuan Gao ₂ , Hai Jin ₃ , Jun He ₁ , Xian-Lei Sheng ₂ , Wentao Jin ₂ , Ziyu Chen ₂ , Wei Li _{2,

4,

5}

Affiliation

The criticality-enhanced magnetocaloric effect (MCE) near a field-induced quantum critical point (QCP) in the spin systems constitutes a very promising and highly tunable alternative to conventional adiabatic demagnetization refrigeration. Strong fluctuations in the low-

T

quantum critical regime can give rise to a large thermal entropy change and thus significant cooling effect when approaching the QCP. In this work, through efficient and accurate many-body calculations, we show there exists a significant inverse MCE (iMCE) in the spin-1 quantum chain materials (

{CH}_{3})_{4} NNi {({NO}_{2})}_{3}

(TMNIN) and

{NiCl}_{2} − 4 SC {({NH}_{2})}_{2}

(DTN), where DTN has substantial low-

T

refrigeration capacity while requiring only moderate magnetic fields. The iMCE characteristics, including the adiabatic temperature change

Δ T_{ad}

, isothermal entropy change

Δ S

, differential Grüneisen parameter, and the entropy change rate, are obtained with quantum many-body calculations at finite temperature. The cooling performance, i.e., the efficiency factor and hold time, of the two compounds is also discussed. Based on the many-body calculations on realistic models for the spin-chain materials, we conclude that the compound DTN constitutes a very promising and highly efficient quantum magnetic coolant with pronounced iMCE properties. We advocate that such quantum magnets can be used in cryofree refrigeration for space applications and quantum computing environments.

中文翻译：

量子临界诱导的显着逆磁热效应

自旋系统中场致量子临界点（QCP）附近的临界增强磁热效应（MCE）构成了传统绝热退磁制冷的非常有前途且高度可调的替代方案。低位剧烈波动

吨

当接近 QCP 时，量子临界状态会引起大的热熵变化，从而产生显着的冷却效果。在这项工作中，通过高效准确的多体计算，我们表明自旋 1 量子链材料中存在显着的逆 MCE（iMCE）（

{CH}_{3})_{4} 镍 {(不_{2})}_{3}

(TMNIN) 和

{氯化镍}_{2} - 4 标准委员会 {({NH}_{2})}_{2}

(DTN)，其中 DTN 具有显着的低

吨

制冷能力强，同时只需要中等磁场。iMCE 特性，包括绝热温度变化

Δ 吨_{广告}

, 等温熵变

Δ 秒

、微分 Grüneisen 参数和熵变率是在有限温度下通过量子多体计算获得的。还讨论了两种化合物的冷却性能，即效率因子和保持时间。基于对自旋链材料真实模型的多体计算，我们得出结论，复合 DTN 构成了一种非常有前途且高效的量子磁性冷却剂，具有显着的 iMCE 特性。我们主张这种量子磁铁可用于空间应用和量子计算环境的无冷冻制冷。

更新日期：2021-07-27

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