Structural and Magnetic Phase Transitions in Chromium Nitride Thin Films Grown by RF Nitrogen Plasma Molecular Beam Epitaxy

Published

September 26, 2017

Author(s)

Khan Alam, Steven M.T. Disseler, William D. Ratcliff, Julie Borchers, Rodrigo Ponce-Perez, Gregorio H. Cocoletzi, Noboru Takeuchi, Andrew Foley, Andrea Richard, David C. Ingram, Arthur R. Smith

Abstract

A magneto-structural phase transition is investigated in single crystal CrN thin films grown by rf plasma molecular beam epitaxy on MgO(001) substrates. While still within the vacuum environment following MBE growth, in-situ variable low-temperature reflection high energy electron diffraction is applied, revealing an in-plane structural transition from 1x1 (primitive CrN unit cell) to √2 x √2-R45° with a transition temperature of 278 K. Ex-situ temperature dependent measurements are also performed, including x-ray diffraction and neutron diffraction, looking at the structural peeks and likewise revealing a first-order structural transition along both [001] and [111] out-of-plane directions, with transition temperatures of 256 K and 268 K, respectively. Turning to the magnetic peaks, neutron diffraction confirms a clear magnetic transition from paramagnetic at room temperature to antiferromagnetic at low temperatures with a sharp, first-order phase transition and a Neel temperature of 270 K or 280 K for two different films. In addition to the experimental measurements of structural and magnetic ordering, we also discuss results from first-principles theoretical calculations which explore various possible magneto-structural models.

Citation

Physical Review B

Volume

96

Issue

10

Pub Type

Journals

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Keywords

Neutron Diffraction, Antiferromagnet, Thin Film: Molecular Beam Epitaxy, Orthorhombic Distortion

Citation

Alam, K. , Disseler, S. , Ratcliff, W. , Borchers, J. , Ponce-Perez, R. , Cocoletzi, G. , Takeuchi, N. , Foley, A. , Richard, A. , Ingram, D. and Smith, A. (2017), Structural and Magnetic Phase Transitions in Chromium Nitride Thin Films Grown by RF Nitrogen Plasma Molecular Beam Epitaxy, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=922967 (Accessed April 27, 2024)