Uniaxial Strain and Hydrostatic Pressure Engineering of the Hidden Magnetism in La1-xCaxMnO3 (0 <= x <= 1/2) Thin Films

Here, using various substrates, we demonstrate that the in-plane uniaxial strain engineering can enhance the Jahn- Teller distortions and promote selective orbital occupancy to induce an emergent anti-ferromagnetic insulating (AFI) phase at x = 1/3 of La1-xCaxMnO3. Such an AFI phase depends not only on the magnitude of epitaxial strain but also on the symmetry of the substrates. Using the large uniaxial strain imparted by DyScO3 (001) substrate, the AFI ground state is achieved in a wide range of doping levels (0 <= x <= 1/2), leaving an extended AFI phase diagram. Moreover, it is found that hydrostatic pressure can tune the AFI phase back to a hidden ferromagnetic metallic phase, accompanied by the formation of accommodation strain. The coaction of the accommodation strain, uniaxial strain, and hydrostatic pressure evolution, and the result may shed light on phase space control of other functional interactions.