The magnetocaloric effect of the Gd-based amorphous composite with Gd nanocrystals

Based on density functional theory of first-principle theory, we systematically investigate the electronic structure and optical property of V-, N- monodoping and V-N codopiong and compare with pure ZnO. The results show that the absorption in the visible light region is enhanced for the doped system, especially for V-N codoped ZnO. The calculated biding energy indicates that the V-N codoping is the most stable system, thus, V-N codoped ZnO is considered as an ideal photocatalyst. Moreover, the method of anion-cation codoping could be better used in photoelectrochemistry and also in the preparation of stable and high performance short wavelength photoelectron devices.

Photocatalysis property of V-N codoped wurtzite ZnO by first-principles study

Qing-Feng¹,

Cui²,

Pan³

et al. 2013

Preparation and properties of polycrystalline and nanocrystalline Sm3Co alloys

Liu¹,

Liu²,

Li³

et al. 2014

In this paper, a novel fabrication process of the nanocrystalline Sm3Co alloys and their fundamental properties were studied. The polycrystalline Sm3Co bulk material was prepared by the vacuum melting method. By using the polycrystalline Sm3Co bulk metal, the nanocrystalline Sm3Co alloys with an average grain size of about 8 nm was prepared by combined ball milling and spark plasma sintering. The crystal structure model was constructed and the magnetic and mechanical properties of the polycrystalline and nanocrystalline Sm3Co alloys were characterized and compared with each other in detail. Results show that the nanocrystalline alloys exhibit magnetic properties and high mechanical properties. Microhardness and elastic modulus of the nanocrystalline Sm3Co alloys are 4.87 GPa and 63.7 GPa, respectively, which are increased by 8.7% and 13.3% as compared with the polycrystalline alloys.

Effects of Co doping on the magnetic properties, entropy change, and magnetocaloric effect in Mn3Sn1-xCoxC1.1compounds

Yan¹,

Sun²,

Wang³

et al. 2014

The Mn3Sn1-xCoxC1.1 compounds are synthesized by a solid-state reaction method. The effects of Co doping on the magnetic properties, phase transition and entropy change are investigated in Mn3Sn1-xCoxC1.1 compounds. The Curie temperature first decreases from 283 K to 212 K (Mn3Sn0.9Co0.1C1.1) with increasing the Co concentration, and then increases to 332 K (Mn3Sn0.2Co0.8C1.1) with further increasing the Co concentration in Mn3Sn1-xCoxC1.1. The first-order transition of Mn3Sn1-xCoxC1.1 gradually changes into the second-order transition, in the mean time, the entropy change decreases and the phase transition region broadens from 9 K to 300 K with increasing the Co content. Both the magnetic entropy change and broadening the transition temperature span can influence the relative cooling power R. Finally we obtain the large R=103 J/kg (H=1.6 MA/m) in Mn3Sn0.8Co0.2C1.1, which could be used as the room-temperature magnetic refrigerant materials.