When the magnetic nanoparticles are smaller than a certain size, they will lose their stable magnetic order (become superparamagnetism); At this size, the anisotropic magnetic energy that keeps the magnetic moment of each particle in a certain direction becomes similar to thermal energy. The information storage industry is trying to find a way to bypass this "superparamagnetic limit". The newly discovered effects include the induction of external anisotropic sources in the form of magnetic exchange coupling between ferromagnetic and antiferromagnetic materials. In the experimental system, ferromagnetic cobalt nanoparticles with a diameter of 4 nm lose their magnetic moment at 10 K when implanted in paramagnetic matrix, but at 290 K in antiferromagnetic matrix. This method should be suitable for any kind of nanoparticle system, including soft materials, hard materials, oxides and metals, so it should be able to help people overcome the superparamagnetic limit in various materials.

Information is too hard to find. . . This seems to be a good academic question. I'm afraid I have to find a medical paper to explain it in detail. I wonder if the information in the link is useful? If I can help you.

. Hk/ scholar? q = % E7 % A3 % 8 1% E6 % 80% A7 % E7 % BA % B3 % E7 % b 1% B3 % E9 % A2 % 97% E7 % B2 % 92 & amp； HL = zh-CN & amp； as _ sdt = 0 & ampas_vis= 1。 oi=scholart