Local electronic structure and magnetic properties of double-perovskite <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>LaCo</mml:mi> <mml:mrow> <mml:mn>0.5</mml:mn> </mml:mrow> </mml:msub> <mml:msub> <mml:mi>N

With x-ray absorption spectroscopy and x-ray magnetic circular dichroism, the element-specific electronic structure and the magnetic interactions of the double perovskite compounds <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:msub> <a:mi>PrCo</a:mi> <a:mrow> <a:mn>0.5</a:mn> </a:mrow> </a:msub> <a:msub> <a:mi>Ni</a:mi> <a:mrow> <a:mn>0.5</a:mn> </a:mrow> </a:msub> <a:msub> <a:mi mathvariant="normal">O</a:mi> <a:mn>3</a:mn> </a:msub> </a:mrow> </a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mrow> <c:msub> <c:mi>LaCo</c:mi> <c:mrow> <c:mn>0.5</c:mn> </c:mrow> </c:msub> <c:msub> <c:mi>Ni</c:mi> <c:mrow> <c:mn>0.5</c:mn> </c:mrow> </c:msub> <c:msub> <c:mi mathvariant="normal">O</c:mi> <c:mn>3</c:mn> </c:msub> </c:mrow> </c:math> were studied. In both compounds, Co and Ni depart from their nominal valence state of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:mrow> <e:mo>+</e:mo> <e:mn>3</e:mn> </e:mrow> </e:math> , implying a charge transfer from Ni to Co. XMCD measurements clearly reveal a ferromagnetic behavior of Co and Ni in both samples. The substitution of La by Pr is isovalent but leads to a partial spin-state transition of <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"> <f:msup> <f:mrow> <f:mi>Co</f:mi> </f:mrow> <f:mrow> <f:mn>3</f:mn> <f:mo>+</f:mo> </f:mrow> </f:msup> </f:math> from high spin to low spin, resulting in a significant decrease in the magnetic moment of Co. Furthermore, a magnetic moment is found on the Pr site as well, with the Pr spin moment oriented antiparallel to those of Co and Ni. This antiferromagnetic coupling is induced by the superexchange interaction between the Pr <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"> <g:mrow> <g:mn>4</g:mn> <g:mi>f</g:mi> </g:mrow> </g:math> and Co/Ni <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"> <h:mrow> <h:mn>3</h:mn> <h:mi>d</h:mi> </h:mrow> </h:math> states.