Abstract
By directly measuring electrical hysteresis loops using the Positive-Up Negative-Down (PUND) method, we determined accurately the remanent ferroelectric polarization of orthorhombic MnO ( Ho, Tm, Yb, and Lu) compounds below their -type spin ordering temperatures. We found that LuMnO has the largest of 0.17 C/cm at 6 K in the series, the value of which allows us to predict that its single-crystal form can produce a of at least 0.6 C/cm at 0 K. Furthermore, at a fixed temperature, decreases systematically with increasing rare earth ion radius from Lu to Ho, exhibiting a strong correlation with the variation of the in-plane Mn–O–Mn bond angle and Mn–O distances. Our experimental results suggest that the contribution of the Mn orbitals may dominate the ferroelectric polarization.
- Received 14 August 2011
DOI:https://doi.org/10.1103/PhysRevB.85.184406
©2012 American Physical Society