3 results about "Magnetic transition temperature" patented technology

This invention discloses a core-shell structured amorphous / nanocrystalline biphase rare-earth-based magnetic refrigeration material, its preparation method, and its applications, belonging to the field of magnetic refrigeration technology. The chemical formula of this material is Gd. x M y Cu z Where 90≤x≤95, 1≤y≤5, 1≤z<5, and y>z, and M is selected from any one of Fe, Co, and Ni; its microstructure is a core-shell dual-phase structure consisting of an amorphous shell encapsulating a nanocrystalline nucleus. This material exhibits more than two magnetic transition temperatures, and its magnetic entropy change curve shows two / three peaks, with a maximum magnetic entropy change of 5.4–6.9 J kg under a 5 T applied magnetic field. ‑1 K ‑1 The magnetic refrigeration temperature range reaches 106-220 K, with a relative refrigeration capacity of 731-1265 J / kg. This material combines high magnetic entropy change, wide refrigeration temperature range, excellent chemical stability, and high service reliability, making it suitable for widespread application as a magnetic refrigerant in the field of green solid-state refrigeration.

The application relates to the technical field of magnetoelectric ceramic materials, in particular to a tungstate manganese hafnium ceramic material based on vacancy and chemical disorder regulation and a preparation method and application thereof. 1‑x Hf x WO4, wherein the hafnium doping amount ranges from 0 < x <= 0.20; in the tungstate manganese hafnium ceramic material Mn 1‑x Hf x WO4, the Hf 4+ Mn 2+ is replaced to introduce vacancy defects and chemical disorder, so as to regulate the magnetoelectric performance of the tungstate manganese hafnium ceramic; the prepared Mn 1‑x Hf x WO4 magnetoelectric ceramic material has a single-phase structure, excellent dielectric performance, significantly improved magnetic transition temperature, expanded ferroelectric polarization temperature range, and obvious magnetic dielectric characteristics, and has very excellent characteristics.

[Problem] To provide a bed for an active magnetic regenerator (AMR) refrigerator and an AMR refrigerator having fewer stages of magnetocaloric members and also having excellent cooling capacity. [Solution] In the present invention, a heat storage body 3 is arranged in the center of a plastic tube 2, and a circular hole 3a is formed in the center of the heat storage body 3. Magnetocaloric members 4a, 4b that are porous and allow permeation of a fluid are loaded on both sides of the heat storage body 3 which serves as the boundary therebetween. A magnetic transition temperature T1 of the magnetocaloric member 4a and a magnetic transition temperature T2 of the magnetocaloric member 4b satisfy T1>T2.