I am observing saturation magnetization higher than the expected value for a metallic-ferromagnet film deposited on a conducting-paramagnet substrate. Additional magnetization is coming from proximity effect. If someone knows a theoretical or experimental reference please share with me.
The proximity effect depends on the nature of the paramagnetic material, but in the case of a true paramagnet (ferromagnet above its ordering temperature as opposed to a diamagnet) then the effect comes from the interfacial exchange coupling between the layers. The exchange coupling is typically hundreds of Tesla and so polarizes a thin interface layer in the paramagnet, giving a small additional magnetization. Although I am not aware of any immediate references, this effect is easily calculated using an atomistic spin model simulation, such as VAMPIRE (http://vampire.york.ac.uk).
Dear Evans and Piramanayagam thanks for your comments. I came back to your comments after a long time sorry to be so slow.
In fact, you are talking about the exchange field coupling between two layers, which may occur only very close to the interface. It may couple antiferromagntically. In case of semiconductor ferromagnetic a ferromagnetic coupling has been observed.
What SN Piramanayagam referred to is not the effect of exchange field. It is just the Pd whic is near ferroamgnetic order s to say acquires a magnetis moment due to the proximity of the Co layer. Pt also shows a similar behaviour.
Dear Ramanathan Krishnan, excuse me for being so late to stimulate the discussion once again. You may be right. My question is how we induce ferrogmagntic order into non-magnetic metal. In case of Co/Pt charge carriers can be increased that can play an important role to induce magnetic order into Pt?
One cannot induce magnetism in any metal. The case of Pd and Pt is special due its band structure. The adjacent ferrromagnetic metal can by polarization electrons induce ferro mag in Pt and Pd.
- Badges
- Science topic
- Similar topics
- Biological Science
- Histology
- Fixatives