  Simultaneous control of magnetic anisotropy and magnetoresistance, especially
with atomic scale precision, remains a pivotal challenge for realizing advanced
spintronic functionalities. Here we demonstrate cooperative continuous control
over both magnetoresistance and magnetic anisotropy in highly strained
La0.7Sr0.3MnO3 (LSMO) thin films. By inserting varying perovskite buffer
layers, compressively strained LSMO films transition from a ferromagnetic
insulator with out-of-plane magnetic anisotropy to a metallic state with
in-plane anisotropy. Atomic-scale buffer layer insertion enables remarkably
acute, precise control to sharply modulate this magnetic phase transformation.
A gigantic 10,000% modulation of the colossal magnetoresistance (CMR) and an
exceptionally sharp transition from out-of-plane to in-plane magnetic
anisotropy are attained in just a few contiguous layers. These atomic-scale
correlations among electronic, magnetic, and structural order parameters yield
flexible multifunctional control promising for next-generation oxide
spintronics.
