Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 71: Correlated Electrons: Poster Session

TT 71.58: Poster

Mittwoch, 18. März 2015, 15:00–18:00, Poster B

Signatures of the magnetostructural phase transition in CrN probed by temperature-dependent infrared spectroscopy — •Jihaan Ebad-Allah1,2, Benjamin Kugelmann1, Francisco Rivadulla3,4, and Christine Kuntscher11Experimentalphysik II, Universitat Augsburg, 86159 Augsburg, Germany — 2Department of Physics, University of Tanta, 31527 Tanta, Egypt — 3Center for Research in Biological Chemistry and Molecular Materials, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain — 4Department of Physical Chemistry, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

During the last decades, CrN has attracted great interest due to its superior high-temperature oxidation resistance, hardness, wear and corrosion resistance, and good chemical and thermal stability. In addition, CrN has remarkable electronic, optical, and magnetic properties. At the Neel temperature (TN= 273-286 K) CrN undergoes a paramagnetic to antiferromagnetic phase transition, concomitant with a structural distortion from cubic rock-salt to orthorhombic [1].

We carried out temperature-dependent absorption measurements on CrN powder in the frequency range 250-7500 cm−1. At ambient conditions, the absorption spectrum shows a phonon mode in the far-infrared range, a strong absorption band at around 0.17 eV, and a charge gap at ≈ 0.7 eV [2]. Below TN , the phonon mode splits and the absorption edge shows a slight blue shift.

[1] A. Filippetti et al., Phys. Rev. B 59, 7043 (1999).

[2] D. Gall et al., J. Appl. Phys. 91, 5882 (2002);

A. Herwadkar et al.,Phys. Rev. B 79, 035125(2009).

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