| Autor: |
Roy AP; Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India., Ss J; Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India., Dwij V; Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, Maharashtra 400076, India., Khandelwal A; Free Electron Laser Utilization Laboratory, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013, India., Chattopadhyay MK; Free Electron Laser Utilization Laboratory, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013, India.; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India., Sathe V; UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore, Madhya Pradesh 452001, India., Mittal R; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.; Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400085, India., Sastry PU; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.; Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400085, India., Achary SN; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.; Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India., Tyagi AK; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.; Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India., Babu PD; UGC-DAE Consortium for Scientific Research, Mumbai Centre, R5-Shed, BARC, Trombay, Mumbai, Maharashtra 400085, India., Le MD; ISIS facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX Oxfordshire, United Kingdom., Bansal D; Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India. |
| Abstrakt: |
Coupling of orbital degree of freedom with a spin exchange, i.e., Kugel-Khomskii-type interaction (KK), governs a host of material properties, including colossal magnetoresistance, enhanced magnetoelectric response, and photoinduced high-temperature magnetism. In general, KK-type interactions lead to deviation in experimental observables of coupled Hamiltonian near or below the magnetic transition. Using diffraction and spectroscopy experiments, here we report anomalous changes in lattice parameters, electronic states, spin dynamics, and phonons at four times the Néel transition temperature (T_{N}) in CrVO_{4}. The temperature is significantly higher than other d-orbital compounds such as manganites and vanadates, where effects are limited to near or below T_{N}. The experimental observations are rationalized using first-principles and Green's function-based phonon and spin simulations that show unprecedentedly strong KK-type interactions via a superexchange process and an orbital-selective spin-phonon coupling coefficient at least double the magnitude previously reported for strongly coupled spin-phonon systems. Our results present an opportunity to explore the effect of KK-type interactions and spin-phonon coupling well above T_{N} and possibly bring various properties closer to application, for example, strong room-temperature magnetoelectric coupling. |
