Physico-Chemical nanomaterials science

Designed and magnetic properties of rare-earth microwires for magnetic tweezers
Dvoretskaya E.V.1, Sidorov V.L.2, Morgunov R.B.1 Koplak O.V.1
1 Institute of Problems of Chemical Physics of the RAS. Semenov, 1, Chernogolovka-142432, Russia.
E-mail: dvoretskaya95@yandex.ru
2 Moscow State University named after M.V. Lomonosov. Lenin mountains, 1, Moscow-119991, Russia.

The new type of the core/shell microwires containing α-Fe core covered with PrDyFeCoB amorphous shell were growth by dropping melt technique [1-3]. In this work, we propose chemical technique of creation of submicron radius of the microwire tip with magnetic states, switchable in external homogeneous magnetic field, for the attaching-detaching of microparticles (Fig 1). 

	Fig.1. SEM image of the thinned microwire tip preliminary magnetized in -100 Oe field with attracted PrDyFeCoB ferromagnetic bead of ~ 1 μm size	
Local and integral magnetization of microware were investigate by SQUID and MOKE technique. Important feature of the hysteresis loop is exchange bias ~ 18 Oe, appearing due to an exchange coupling between ferromagnetic α-Fe core and ferrimagnetic PrDyFeCOB shell.
 
1.	Koplak O.V., Dvoretskaya E.V., Talantsev A.D., Korolev D.V., Valeev R.A., Piskorsky V.P., Denisova A.S., Morgunov R.B. Orientation dependence of the magnetic moment of microwires α-Fe(PrDy)(CoFeB) // Solid state physics. -2020.-62 (4).-P. 562-566.
2.	Morgunov R.B., Koplak O.V., Piskorsky V.P., Korolev D.V., Valeev R.A., Talantsev A.D. JMMM.-2020.-497. -P. 166004.
3.	Koplak O.V., Sidorov V.L., Kunitsyna E.I., Valeev R.A., Korolev D.V., Piskorsky V.P., Morgunov R.B. Bistable and multi-domain states of alpha-Fe/(PrDy)(FeCo)B ferromagnetic microwires // Solid state physics. -2019.-61.-P. 2090-2096.
This work was supported by the scientific project “Stability” 20-32-70025.