The researchers investigated the nature of the structural phase boundary between the two phases of La2NiMnO6 as a function of pressure and temperature, and the correlation between this and its magnetic properties. To do this, they carried out a comprehensive neutron diffraction study of the material over a broad temperature and pressure range using complementary techniques on different beamlines.
La2NiMnO6 has been widely studied, as it is an interesting candidate for potential thin-film spin-based electronics. It has also attracted interest as a potential lead-free material for use in solar cells and, more recently, for use as a cathode material for intermediate temperature solid-oxide fuel cells.
Although widely studied, there have been relatively few explicit investigations into the effects of high pressure on the crystallographic and magnetic properties of La2NiMnO6. While X-rays have provided an accurate measure of the volume changes in the material, they are not well suited to providing further crystallographic information on this compound.
This is due to the similar interactions of X-rays with Ni and Mn and the presence of relatively light O atoms along with heavier La atoms. Neutron diffraction provides much greater contrast, due to the difference in neutron interactions with Ni and Mn and strong neutron scattering from oxygen, even in the presence of heavier components of the unit cell.
By using both I15 at Diamond Light Source and the HRPD, PEARL and Polaris beamlines at ISIS, the group of researchers were able to map comprehensively the structural and magnetic phases of the material under different pressure and temperature conditions.
“This investigation forms part of a wider study to determine the structure property relationships of a range of oxide materials at the extreme conditions of pressure and temperature," explains ISIS instrument scientist Craig Bull; "such studies would not be possible without the dedicated instrumentation and facilities provided at both ISIS and Diamond."
The full paper can be read online at Inorganic Chemistry.
Other science highlights using the ISIS beamlines can be found by following: PEARL, Polaris and HRPD.