resumo
In the present study, the physical properties including structural, optical and magnetic of HoCr1-xMnxO3 (x = 0, 0.15) have been thoroughly investigated and compared. A detailed structural analysis of the compounds provided a way to correlate the optical and magnetic properties with the change in Cr-site ionic radius, tilt angles and distortion in CrO6 octahedra due to Mn substitution. Further, the shift in the Raman phonon modes was associated with the increased structural distortion owing to Mn substitution in HoCrO3 compound. The variation in the Urbach energy values, measured from the diffuse reflectance spectroscopy, was found to be closely related to the octahedral distortion. The optical band gap reduced from 3.22 eV to 2.01 eV after Mn substitution. Other optical parameters such as skin depth, refractive index, extinction coefficient and optical conductivity were also perceived to vary noticeably in the substituted compound. The overall structural distortion with Mn substitution resulted in the decrease of antiferromagnetic transition temperature of the pristine compound. The strong magnetic entropy change was observed at low temperatures in pure HoCrO3 compound and its value was enhanced on Mn substitution. Therefore, the present work provides a convenient method to tune the multifunctional properties of HoCrO3 compound, which has practical applications such as photocatalyst and low-temperature magnetic refrigerant.
categoria
Materials Science, Ceramics
autores
Kanwar, K; Coondoo, I; Anas, M; Malik, VK; Kumar, P; Kumar, S; Kulriya, PK; Kaushik, SD; Panwar, N
nossos autores
Indrani Coondoo
Investigador Júnioragradecimentos
Dr. Neeraj Panwar would like to thank the DST SERB, New Delhi, UGC DAE CSR Mumbai and IUAC New Delhi for the grants through Projects ECR/2017/002681, CRS-M-298 and UFR-62317, respectively. I.C. would like to thank financial assistance by national funds (OE), through FCT -Fundac ~ao para a Ci <^>encia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. The authors would like to thank their colleague Dr. R. K. Verma for fruitful discussion. The authors are also grateful to the Department of Physics, Banasthali Vidyapeeth (India) and Materials Research Centre, MNIT Jaipur (India) for the use of SEM and Raman, FTIR & DRS facilities, respectively.