Absence of moment fragmentation in the mixed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>B</mml:mi></mml:math>-site pyrochlore <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Nd</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>GaSbO</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:mrow></mml:math>
Steven J. Gomez Alvarado, Paul M. Sarte, Micaela Zelensky, Alannah M. Hallas, Benito A. Gonzalez, Ka H. Hong, Edward J. Pace, Stuart Calder, M. B. Stone, Yixi Su, Erxi Feng, Manh Duc Le, C. Stock, J. Paul Attfield, Stephen D. Wilson, C. R. Wiebe, A. A. Aczel
Abstract
Nd-based pyrochlore oxides have garnered significant interest owing to the moment-fragmentation physics observed in Nd${}_{2}$Zr${}_{2}$O${}_{7}$ and speculated in Nd${}_{2}$Hf${}_{2}$O${}_{7}$. Notably, this phenomenon is absent in Nd${}_{2}$Sn${}_{2}$O${}_{7}$, which features a smaller $B$-site ionic radius. Here, bulk characterization and neutron scattering measurements reveal a similar absence of moment fragmentation in Nd${}_{2}$GaSbO${}_{7}$, which is characterized by significant $B$-site disorder and an extremely small average ionic radius on the $B$ site. These results may indicate that chemical pressure (and not necessarily the $B$-site disorder) plays a key role in the presence or absence of this exotic phenomenon.