A high frequency magnetocooling cycle and direct Delta T measurements in ferroic thin films and low volume samples

铁质薄膜和小体积样品中的高频磁冷却循环和直接 Delta T 测量

• 批准号: 226686525
• 负责人: Professor Dr. Daniel Hägele
• 金额: --
• 依托单位: Institut für Experimentalphysik VI: AG Spektroskopie der kondensierten Materie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/226686525?language=en
• 关键词: frequency; magnetocooling; cycle; direct; Delta

We will investigate the adiabatic temperature change Delta T and dissipative heating in magnetocaloric and electrocaloric samples under cyclic field changes. Such measurements are required for identifying high performance materials within the priority programme that will be the basis of future cooling devices with high efficiency. The measurements will be based on our modulation infrared thermometry (MIT) setup, that proved to be capable of detecting Delta T with sub-mK resolution and gave worldwide the first Delta T data on a thin film sample. We want to install a new magnet for operating MIT with magnetic field amplitudes of more than 1~T and frequencies reaching 100~Hz. High fields are required to investigate samples under conditions that mimic a future cooling device. High frequencies allow for the investigation of thin film materials libraries as the determination of the temperature is faster than heat diffusion. Electrocaloric materials (namely highly dielectric relaxor materials) will be investigated regarding their temperature dependent Delta T, their frequency dependent behavior, their dissipative heating, and long time-relaxation behavior (aging) for different measurement protocols. We will continue our activities on a high frequency magnetocaloric cooling devices.

我们将研究磁场循环变化下磁热和电热样品的绝热温度变化δ T和耗散加热。这些测量是在优先方案中确定高性能材料所必需的，这些材料将成为未来高效冷却装置的基础。测量将基于我们的调制红外测温仪（MIT）装置，该装置已被证明能够以低于mk的分辨率检测δ T，并在全球范围内提供薄膜样品上的第一个δ T数据。我们想安装一个新的磁体来操作MIT，磁场振幅大于1~T，频率达到100~Hz。在模拟未来冷却装置的条件下，需要高场来研究样品。高频率允许研究薄膜材料库，因为温度的测定比热扩散快。对于不同的测量方案，将研究电热材料（即高介电弛豫材料）的温度依赖δ T，频率依赖行为，耗散加热和长时间弛豫行为（老化）。我们将继续研究高频磁热冷却装置。