Neutron diffraction, dc electric resistivity, and ac magnetic susceptibility measurements were performed to study the structural, electric, and magnetic properties of naturally bilayered La1.02Sr1.98Mn2O7. An insulator to metal transition was clearly seen at approximately 170 K. Below 60 K, the system reentered the insulating state. Three-dimensional (3D) long-range order of the Mn spins was found, with an ordering temperature of Tm≈180 K and a saturated moment of 〈μz〉 = 2.70(2)μB. The in-plane couplings were ferromagnetic. Within each bilayer, simple antiferromagnetic couplings between the ferromagnetic sheets were found, whereas the neighboring bilayers were coupled ferromagnetically. A structural change that results in a reduction of the thermal contraction rate occurs at approximately 250 K as well.
|Number of pages||6|
|Journal||Materials Science and Engineering B: Solid-State Materials for Advanced Technology|
|State||Published - 29 Sep 2000|