Unusual dielectric response in B-site size-disordered hexagonal transition metal oxides

作者：Choudhury Debraj^*; Venimadhav Adyam; Kakarla Chandrasekhar; Delaney Kris T; Devi P Sujatha; Mondal P; Nirmala R; Gopalakrishnan J; Spaldin Nicola A; Waghmare Umesh V; Sarma D D

来源：Applied Physics Letters, 2010, 96(16): 162903.

DOI：10.1063/1.3379293

We discover that hexagonal holmium copper titanate (Ho2CuTiO6), has a unique and highly desirable combination of high dielectric constant, low losses, very small temperature coefficient, and low frequency dependence. Our first-principles calculations indicate that these exceptional properties result from a size-difference at the Cu/Ti B-site that suppresses the expected ferroelectric transition, combined with the dominance of intermediate-frequency polar vibrational modes in the dielectric response. Our results suggest that the use of such B-site disorder in alloys of hexagonal transition-metal oxides should generally result in similar robust dielectrics.

• 出版日期2010-4-19