5 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.

The invention relates to a two-dimensional Van der Waals magnet and a preparation method and application thereof, the chemical formula of the two-dimensional Van der Waals magnet is Fe2. 8PdxGaTe2, and x is equal to 0.1 + / -0.03. The paramagnetic transition temperature of the two-dimensional Van der Waals magnet is 310-325K, and the two-dimensional Van der Waals magnet can generate a magnetic Skyrmion magnetic domain structure with high density and small size (less than 50nm) at room temperature. The two-dimensional Van der Waals magnet is a dissociable single crystal block. The preparation method of the two-dimensional Van der Waals magnet comprises the following steps: weighing the raw materials in proportion, and then preparing the Fe2. 8PdxGaTe2 single crystal material by adopting a high-temperature fluxing agent method. The two-dimensional Van der Waals magnet has wide application scenarios in magnetic storage materials and spintronics devices. Compared with the prior art, the two-dimensional Van der Waals magnet provided by the invention has excellent comprehensive performance, the preparation process is simple, industrial production is easy, and the two-dimensional Van der Waals magnet is an ideal candidate material of spintronics devices for magnetic storage, information conversion and the like.

[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.

The invention discloses a single crystal / polycrystal single-phase composite structure thin film with magnetoresistance response in a wide temperature range and a preparation method thereof. The preparation method comprises the following steps: preparing an LSMO single crystal thin film with cracks on a target substrate through a water-soluble sacrificial layer technology; and depositing an LSMO thin film with a single-crystal / polycrystal homogeneous composite structure on an LSMO single-crystal thin film with cracks through a pulse laser deposition technology to form a single-crystal / polycrystal single-phase composite structure thin film with wide-temperature-range magnetoresistance response. Two different nucleation sites of an LSMO single crystal film and a non-lattice matching substrate exposed at a crack are introduced on a target substrate, and then high-temperature pulse laser deposition is carried out. A boundary structure is designed, namely, a controllable polycrystalline LSMO thin film is artificially introduced into a high-quality single crystal LSMO thin film, and by means of local spin disorder existing on a polycrystalline grain boundary and the difference of ferromagnetic-paramagnetic transition temperatures of the single crystal LSMO thin film and the polycrystalline LSMO thin film, the response temperature of the magnetoresistor is remarkably widened.