Synthesis, structural and magnetic studies of the CuCr 1− x Rh x O 2 delafossite solid solution with 0 ≤ x ≤ 0.2

• Published in: Materials research bulletin Vol. 46; no. 10; pp. 1729 - 1733
• Main Authors: Amami, M., Jlaiel, F., Strobel, P., Ben Salah, A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2011
• Subjects: C. Raman spectroscopy; C. Raman spectroscopy
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2011.05.033

[Display omitted] ► Rh non-magnetic replacement of the Cr in the magnetic frustrated delafossite CuCrO 2. ► Delafossite solid solution is maintained up to 0.2 in this system. ► Strain generated by Rh substitution is strongly anisotropic. ► M 3+–O bond strength is affected. ► High temperature paramagnetic behavior and weak ferromagnetism at low temperature. The CuCr 1− x Rh x O 2 series is investigated by X-ray diffraction, magnetization measurements and Raman spectroscopy on ceramic samples. It is found that a delafossite solid solution is maintained up to x = 0.2 in CuCr 1− x Rh x O 2. The small observed variation in cell parameters is consistent with the small difference between the ionic radii of Cr 3+ and Rh 3+. A significant broadening of X-ray reflections is observed and when analyzed using the Williamson–Hall relationship showed that the strain generated by Rh substitution is strongly anisotropic, affecting mainly (Cr,Rh)–O bonds in the ab plane. Room temperature Raman spectra displayed three main Raman active modes. All modes shift to lower frequency and undergo significant changes in intensity with increasing Rh content, showing the effect of Rh atoms on the M 3+–O bond strength. The magnetic behavior of CuCr 1− x Rh x O 2 samples was investigated as a function of temperature and applied field. At high temperature paramagnetic behavior, and at low temperature, evidence for weak ferromagnetism, reinforced by a hysteresis loop at 4 K is observed. The magnetic behavior of CuCr 1− x Rh x O 2 is attributed to the disorder of Cr and Rh in octahedral sites resulting in short-range Cr–O–Cr and Cr–O–Rh interactions, which give rise to short-range weak ferromagnetism.