Tunable magnetocaloric effect around room temperature by Fe doping in Mn0.98Cr(0.02-x)FexAs compound

Author(s)

Ipus, Jhon J. ; Ribeiro, Paula O. ; von Ranke, P. ; Caraballo Vivas, R. J. ; Carvalho, Alexandre M. G. ; Coelho, Adelino A. ; Franco, Victorino ; Rocco, Daniel L.

• Document type: Journal article
• Source: Journal of Magnetism and Magnetic Materials; v. 436, p. 85-90, AUG 15 2017.
• Web of Science Citations: 3

Abstract

In this work, we present an investigation of the magnetic and magnetocaloric properties of Mn0.98Cr((0.02-x))FexAs compounds with x = 0.002, 0.005 and 0.010. Our findings show that as Fe content increases the unit cell volume decreases, which indicates that Fe doping emulates the pressure effect on the crystalline structure. The transition temperature T-C decreases as x increases and it can be set at approximate value of room temperature by changing the doping level. In addition, the magnetic entropy change Delta S-M was determined using a discontinuous measurement protocol, and realistic values from the magnetocaloric effect presented by MnAs-type compounds under pressure (emulated pressure) could be obtained. The values of Delta S-M(MAX) are very large, around -11 J kg(-1) K-1 with Delta H = 15 kOe, which is higher than that observed for most compounds with TC around room temperature. However, Delta S-M is confined to a narrow temperature range of 11 K. To overcome this drawback, the composition of a theoretical composite formed by our samples was calculated in order to obtain a table-shaped Delta S-M curve. The simulated composite showed a high value of full width at half maximum delta T-FWHM of 33 K, which is much higher than that of single sample. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/03480-0 - Magnetocaloric effect and barocaloric effect: new experimental techniques, materials and theoretical models
• Grantee: Alexandre Magnus Gomes Carvalho
• Support Opportunities: Research Grants - Young Investigators Grants