Field Modulated Intrinsic Positive Exchange Bias in Novel Ferrite Ru$_{0.25}$Cr$_{0.75}$O$_{2}$ near the Compensation Point

In some ferrimagnetic materials systems a compensation point is observed where the opposing sublattice magnetizations are equal and opposite resulting in a zero net magnetization. The resulting magnetization decreases below zero at temperatures below T$_{c}$ and then increase to zero at T$_{c}$. We observe this type of unusual ferrimagnetic behavior in the Ru$_{0.25}$Cr$_{0.75}$O$_{2}$ system. In addition, near the compensation point we observe positive exchange bias that can be modulated using an external applied magnetic field. Possible mechanisms will be discussed.