AC-specific heat measurements remain as the foremost thermodynamic experimental method to underpin phase transitions in tiny samples. However, its performance under combined extreme conditions of high-pressure, very low temperature and intense magnetic fields needs to be broadly extended for investigation of quantum phase transition in strongly correlated electron systems. In this communication, we discuss the determination of specific heat on the quantum paramagnetic$-$insulator SrCu$_{2}$(BO$_{3}$)$_{2}$ by applying the AC-specific heat technique under extreme conditions. In order to apply this technique to insulating samples we sputtered a metallic thin film-heater and attached thermometer onto sample. Besides that, we performed full frequency scans with the aim to get quantitative specific heat data. Our results show that we can determine the sample heat capacity within 5$\%$ of accuracy respect to an adiabatic technique. This allows to uncover low energy scales that characterize the ground state of quantum spin entanglement in SrCu$_{2}$(BO$_{3}$)$_{2}$.
Comparative study of helimagnets MnSi and Cu2OSeO3 at high pressures
本文用交流量热法研究了高压下螺旋磁体Cu_2OSeO_3和MnSi的热容。尽管它们的磁矩性质不同，但Cu2OSeO3和MnSi在相变时的磁性和热力学性质的行为表现出惊人的相似性。如果作为温度的函数进行分析，则两种物质（峰和肩）在相变时的热容的两个特征在高压下也以类似的方式表现。这可能意味着像MnSi这样的弱巡回磁体的典型纵向自旋波动对相变的贡献很小。热容量曲线的肩部随着温度的降低而收缩，这表明它们来自经典涨落。在MnSi的情况下，尖锐的峰和肩部的热容同时消失，可能意味着存在一个三临界点，并确认在MnSi以及在Cu 2 OSe O 3的一级相变的波动性质。
Heat-Capacity Measurements of Energy-Gap Nodes of the Heavy-Fermion Superconductor CeIrIn5 Deep inside the Pressure-Dependent Dome Structure of its Superconducting Phase Diagram
AC-Calorimetry at High Pressure and Low Temperature
讨论了适应高压实验需要的交流量热技术的最新发展。用Bridgman型压室和金刚石对顶压室在0.1 K < T ~ 1.5 K的温度范围内半定量测量比热是可能< 10 K. The pressure transmitting medium used to ensure good pressure conditions determines to a great extent via its thermal conductivity the operating frequency and thus the accessible temperature range. Investigations with different pressure transmitting media for T >的，固体He的截止频率比滑石的高得多。低于1 K和压力高于10 GPa的实验清楚地表明，可以测量比热的线性温度系数的压力依赖性。这是在定性协议的相关数量获得准同时通过电阻率测量相同的样品。
