= Solution
Heat the bilayer into a window \b[$T_N<T<T_c$], apply an in-plane <magnetic field> sufficient to align the <ferromagnet>, and cool through the <antiferromagnet>'s ordering/blocking range while retaining the field. The <ferromagnet> supplies a preferred interfacial spin direction as the <antiferromagnet> orders. Sufficient antiferromagnetic anisotropy then pins part of the interfacial spin configuration, producing <unidirectional magnetic anisotropy> rather than merely <uniaxial magnetic anisotropy> in the <ferromagnet>.
Measure a full major <hysteresis> loop after removing the cooling field, and compare with the isolated <ferromagnet>, a zero-field-cooled bilayer and the result of reversing the cooling-field direction. Those controls separate a true loop-centre shift from a changed coercive width, minor-loop artefacts or trapped applied field. The effect requires appropriate interfacial exchange and stable pinning; an ideally compensated or freely rotating interface need not produce a large bias. Exchange anisotropy in coupled ferromagnetic/antiferromagnetic material was demonstrated in the classic experiment below.<New Magnetic Anisotropy by W. H. Meiklejohn and C. P. Bean>[Physical Review 102 (1956), pp. 1413–1414]{ref}
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