In a process for producing organic substrate particles bonded to switchable ferromagnetic nanoparticles with a mean particle diameter in the range from 10 to 1000 nm, the ferromagnetic nanoparticles used are those nanoparticles which are nonferromagnetic at first, but become ferromagnetic when the temperature is lowered, these at first nonferromagnetic nanoparticles in dispersed form are bonded to the organic substance particles, and then the nanoparticles bonded to the substrate particles are made ferromagnetic as a result of the temperature being lowered.本發明係關於一種製造鍵結至具有10至1000 nm之平均粒徑之可切換鐵磁性奈米粒子之有機物質粒子之方法,其中,所使用之鐵磁性奈米粒子係最初為非鐵磁性,但當溫度降低時變得具有鐵磁性之彼等奈米粒子,將此等呈分散形式之最初非鐵磁性奈米粒子鍵結至有機物質粒子,及隨後使得鍵結至物質粒子之奈米粒子由於溫度降低而變得具有鐵磁性。(無元件符號說明)
