Evidence for Spin Swapping in an Antiferromagnet

In the past decades, climate change and an energy crisis have prompted researchers to focus on improving the efficiency of power-saving and energy conversion devices. Thermoelectric generation is a key materials-based idea with great potential in applications.

J. Zhou (U. Texas-Austin); G. Fiete (Northeastern U.); C.L. Chien (Johns Hopkins U.)

In the past decades, climate change and an energy crisis have prompted researchers to focus on improving the efficiency of power-saving and energy conversion devices. Thermoelectric generation is a key materials-based idea with great potential in applications.

 

Spin  caloritronics  is  an  emerging  field  with  great  potential  for building  a  new  type  thermoelectric  device  with  an  efficiency exceeding  the  limit  imposed  by  a  single  material  in  conventional thermoelectric  devices.  As  a  key  phenomena  of  spin  caloritronic devices, a voltage induce via a temperature gradient parallel to the interface, as shown in the figure on the right, has been missing.

 

We have demonstrated the desired response in the canted spin antiferromagnet LaFeO3 with the coating of heavy metals of Pt and W, and provided a thorough investigation of the vector spin Seebeck effect associated with the antiferromagnet. Remarkably, the thermal voltage generated via the parallel temperature gradient in LaFeO3 is comparable  to  the longitudinal spin Seebeck  effect  (perpendicular temperature  gradient)  found  in  the  well  studied  Y3Fe5O12(YIG)/Pt system. The unique response in LaFeO3/Pt can be accounted for by a  spin swapping model proposed by the team in the citation below.

Designing Materials to Revolutionize and Engineer our Future (DMREF)