Interstitial-nitrogen effect on phase transition and magnetocaloric effect in Mn(As,Si) (invited)

Authors

W. B. Cui, Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Center for Materials Physics, Chinese Academy of Sciences
X. K. Lv, Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Center for Materials Physics, Chinese Academy of Sciences
F. Yang, Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Center for Materials Physics, Chinese Academy of Sciences
Ralph Skomski, University of Nebraska-LincolnFollow
Y. Yu, University of Nebraska-Lincoln
X. G. Zhao, Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Center for Materials Physics, Chinese Academy of Sciences
W. Liu, Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Center for Materials Physics, Chinese Academy of Sciences
Z.D. Zhang, Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Center for Materials Physics, Chinese Academy of Sciences

Date of this Version

2010

Comments

Published in JOURNAL OF APPLIED PHYSICS 107, 09A938 (2010). Copyright © 2010 American Institute of Physics. Used by permission.

Abstract

The effect of interstitial nitrogen on the phase transition and magnetocaloric behavior of MnAs_1−xSi_xN_δ (x=0.03, 0.06, and 0.09) is investigated. The interstitial nitrogen atoms cause the step-scanned x-ray diffraction peaks to shift toward lower angles and lower the Curie temperature, whereas silicon addition increases the Curie temperature to near room temperature. The thermal hysteresis is reduced to nearly 0 in MnAs_1−xSi_xN_δ, which is beneficial to practical applications. For a field change of 5 T, the largest magnetic entropy change and refrigerant capacity are 14.6 J kg⁻¹ K⁻¹ at 247 K and 360 J kg⁻¹, which is slightly higher than the entropy change in the parent alloy. Finally, we briefly discuss the occurrence and origin of the “virgin effect” in MnAs.