Giant magnetocaloric effect in nanostructured Fe-Co-P amorphous alloys enabled through pulse electrodeposition

Abstract

In this work, amorphous Fe-Co-P films prepared by electrodeposition are found to exhibit dense microstructures with amorphous grains. Through a pulse electrodeposition synthesis route, complex microstructures containing nano-sized grains are obtained in the amorphous alloy films. The nanostructured Fe-Co-P amorphous alloys show superior soft magnetic and magnetocaloric properties as compared with those of other iron-based soft magnetic amorphous alloys reported to date. The coercive field of samples can be as small as 1.6 Oe at room temperature. The magnetocaloric effect (MCE) of the ternary amorphous alloys has been investigated by evaluating the magnetic entropy changes, |∆S M |, from their temperature-dependent magnetization behaviors. The |∆S M | values are as high as 1.846 J kg −1 K −1 with an applied magnetic field of 10 kOe. With a temperature span of 90 K, the refrigerant capacity of samples can be as high as 118.64 J kg −1 . The nanostructure enabled giant MCE in Fe-Co-P amorphous alloys is discussed.

Магнитные свойства и магнитокалорический эффект в пленках и микропроводах Gd

“…Еще один сравнительно современный подход к совершенствованию таких сплавов заключается в поиске МКЭ в нано-и микроструктурах тех сплавов, которые демонстрируют наилучшие свойства в макроскопическом состоянии [7][8][9][10]. Это объясняется следующими дополнительными факторами, способными оптимизировать МКЭ в нано-или микроструктурах: высокими микронапряжениями, присутствием долгоживущих неравновесных метастабильных фаз, не существующими в макроскопических образцах, значительным улучшением теплообмена в мелкодисперсной среде, состоящей из микро-или наноструктур.…”

Magnetic properties and magnetocaloric effect in Gd films and microwires

“…One more relatively modern approach to the improvement of such alloys consists in the search for MCE in nanoand microstructures of the alloys that demonstrate the best properties in the macroscopic state [7][8][9][10]. This is due to the following additional factors, which are able to optimize MCE in nano-or microstructures: high microstresses, the presence of long-lived nonequilibrium metastable phases that do not exist in macroscopic samples, the considerable improvement of heat exchange in a finely dispersed medium composed of micro-or nanostructures.…”

Histological and mechanical properties of laser-melted carbon nanotube-toughened Fe-based amorphous coatings

“…The internal atomic arrangement of Fe-based amorphous alloys is not as orderly as that of crystalline alloys but has a disordered structure, which usually exhibits more properties than crystalline alloys, including high strength, high hardness, excellent wear and corrosion resistance, etc. [3]- [5]. However, the preparation of bulk amorphous alloys requires great cooling conditions, which limits the use of Fe-based amorphous alloys with excellent properties as structural materials [6]- [7].…”