Insight into the structural and magnetotransport properties of epitaxial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>α</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mi>Fe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:mi>Pt</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:mn>111</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> heterostructures: Role of the reversed layer…

We report on the chemical structure and spin Hall magnetoresistance (SMR) in epitaxial $\alpha$-Fe$_2$O$_3$(hematite)(0001)/Pt(111) bilayers with hematite thicknesses of 6 nm 15 grown by molecular beam epitaxy a MgO(111) substrate. Unlike previous studies that involved Pt overlayers hematite, present films were stable buffer layer displayed structural changes as function thickness. These differences (the presence ferrimagnetic phase thinner film) significantly affected magnetotransport properties bilayers. observed sign change SMR from positive to negative when thickness increased nm. For $\alpha$-Fe$_2$O$_3$(15 nm)/Pt, we demonstrated room-temperature switching N\'eel order rectangular, nondecaying characteristics. Such structures open way extending more complex systems double asymmetric metal/hematite/Pt interfaces.