TY - JOUR
KW - Thin films
KW - Binary alloys
KW - Ferromagnetism
KW - Exchange coupling
KW - Antiferromagnetic materials
KW - Ferromagnetic materials
KW - Frequency modulation
KW - Image enhancement
KW - Rhodium alloys
KW - Antiferromagnetics
KW - Antiferromagnets
KW - Exchange coupled
KW - Ferromagnet heterostructures
KW - Ferromagnetic layers
KW - First-order phase transitions
KW - In-plane orientation
KW - Temperature range
KW - Iron alloys
AU - I Gray
AU - G.M Stiehl
AU - J.T Heron
AU - A.B Mei
AU - D.G Schlom
AU - Ramamoorthy Ramesh
AU - D.C Ralph
AU - G.D Fuchs
AB - Uncompensated moments (UMs) in antiferromagnets are responsible for exchange bias in antiferromagnet/ ferromagnet heterostructures; however, they are difficult to directly detect because any signal they contribute is typically overwhelmed by the ferromagnetic layer. We use magnetothermal microscopy to image micron-scale uncompensated moments in thin films of FeRh, a room-temperature antiferromagnet that exhibits a first-order phase transition to a ferromagnetic (FM) state near 400 K. FeRh provides the unique opportunity to study both uncompensated moments in the antiferromagnetic (AF) phase and the interaction of uncompensated moments with emergent ferromagnetism within a relatively broad (390-420 K) temperature range near TC. In the AF phase below TC, we image both pinned UMs, which cause local vertical exchange bias, and unpinned UMs, which exhibit an enhanced coercive field that reflects exchange-coupling to the AF bulk. Near TC, where AF and FM order coexist, we find that the emergent FM order is exchange-coupled to the bulk Néel order. This exchange coupling leads to the nucleation of unusual configurations in which FM domains are pinned in different in-plane orientations, even in the presence of a nominally saturating magnetic field, before suddenly collapsing into a state uniformly parallel to the field. © 2019 American Physical Society.
BT - Physical Review Materials
DO - 10.1103/PhysRevMaterials.3.124407
LA - eng
M1 - 12
N1 - cited By 2
N2 - Uncompensated moments (UMs) in antiferromagnets are responsible for exchange bias in antiferromagnet/ ferromagnet heterostructures; however, they are difficult to directly detect because any signal they contribute is typically overwhelmed by the ferromagnetic layer. We use magnetothermal microscopy to image micron-scale uncompensated moments in thin films of FeRh, a room-temperature antiferromagnet that exhibits a first-order phase transition to a ferromagnetic (FM) state near 400 K. FeRh provides the unique opportunity to study both uncompensated moments in the antiferromagnetic (AF) phase and the interaction of uncompensated moments with emergent ferromagnetism within a relatively broad (390-420 K) temperature range near TC. In the AF phase below TC, we image both pinned UMs, which cause local vertical exchange bias, and unpinned UMs, which exhibit an enhanced coercive field that reflects exchange-coupling to the AF bulk. Near TC, where AF and FM order coexist, we find that the emergent FM order is exchange-coupled to the bulk Néel order. This exchange coupling leads to the nucleation of unusual configurations in which FM domains are pinned in different in-plane orientations, even in the presence of a nominally saturating magnetic field, before suddenly collapsing into a state uniformly parallel to the field. © 2019 American Physical Society.
PB - American Physical Society
PY - 2019
T2 - Physical Review Materials
TI - Imaging uncompensated moments and exchange-biased emergent ferromagnetism in FeRh thin films
VL - 3
SN - 24759953
ER -