The effects of chromium substitution on the electronic and magnetic properties of CuFeO2
Journal of Optoelectronics and Advanced Materials, cilt.27, sa.5-6, ss.271-280, 2025 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 27 Sayı: 5-6
- Basım Tarihi: 2025
- Dergi Adı: Journal of Optoelectronics and Advanced Materials
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex
- Sayfa Sayıları: ss.271-280
- Anahtar Kelimeler: Magnetic materials, Oxides, PPMS, XAFS
- Çukurova Üniversitesi Adresli: Evet
Özet
We present a comprehensive investigation of chromium-substituted delafossite CuFe1-xCrxO2 using synchrotron X-ray diffraction (SR-XRD), X-ray absorption fine structure (XAFS) spectroscopy, and physical property measurements (10-300 K). The studied pristine CuFeO2 exhibits a stable dual-phase structure comprising dominant trigonal-rhombohedral (R-3m, 87.7 wt%) and minor hexagonal (P62/mmc, 12.3 wt%) polymorphs, which persists throughout chromium substitution. Structural analysis reveals chromium incorporation nucleates a secondary hexagonal CuCrO2 phase (P63/mmc) while preserving the host matrix's oxygen stoichiometry, attributable to stronger Fe-O versus Cr-O bonding. XAFS confirms maintained Fe3+ coordination geometry and minimal framework disruption despite Cr substitution. Remarkably, all substituted samples display soft ferromagnetism throughout 10-300 K, contrasting with pure CuFeO2's antiferromagnetic ordering below 11-14 K. This emergent ferromagnetism originates from competing exchange interactions, where introduced ferromagnetic Cr3+-O-Cr3+ pathways (J ≈ +15.4 K) coexist with native antiferromagnetic Fe3+-O-Fe3+ couplings (J ≈-8.2 K). The findings demonstrate chromium's dual role as both structural stabilizer and magnetic modifier in delafossite oxides.