This document discusses using FORC differential dissection to analyze soft biphase magnetic ribbons. It presents three samples - a soft sample containing an amorphous matrix, a hard sample with no amorphous matrix, and a biphase sample containing both hard and soft phases. FORC differential dissection can discriminate between magnetic phases and identify dominant interactions. In the soft sample, the amorphous matrix produces a peak in the SFD and negative coupling spots. In the hard sample, these features also indicate positive coupling. In the biphase sample, the peaks move closer together, also showing positive mutual interaction between the phases.

1. FORC differential dissection of soft biphase
magnetic ribbons
J.C. Martínez-García*, M. Rivas*, D. Lago-Cachón, J.A. García
Departamento de Física de la Universidad de Oviedo, Edificio Departamental Este, Campus de Viesques,
33204 Gijón, España.
*Emails: jcmg@uniovi.es, rivas@uniovi.es
Unravelling the information contained in First Order Reversal Curves (FORC) is a hot topic. FORC
differential dissection leads to a simple physical interpretation of both the SFDs and the FORC di-
agrams, eluding the usual reference to the CPM which is not generally applicable. The technique
provides a systematic procedure of discriminating the magnetic phases as well as the dominant
interactions in multiphase systems.
 Soft Sample: Co69B12Si12Fe4Mo2Ni1 ribbon annealed
at 505C for 30 min with incipient precipitation of hcp
Co crystallites. The peak in the SFD comes from the soft
residual amorphous matrix.
The shift of the ascending side of the peak produces
the negative interaction spot (I-spot), due to a positive
coupling.
The disappearance of the hard-phase plateau produc-
es the extinction spot (E-spot) which emerges below
the H=-Hr axis due again to the positive coupling.
The scheme shows how the evolution of the SFD with
the reversal field is related to the sign of the interac-
tion.
Nano
Bio
Análisis
 Hard Sample: Annealed at
520C for 30 min producing total
disappearance of the soft amor-
phous matrix.
We observe as well the distinc-
tive features of positive cou-
pling.
 Biphase Sample: Annealed at
510C for 30 min producing a
hard-soft magnetic system.
Both peaks get closer respect to
their position in the monophase
SFDs, indicating positive mutual
interaction.
Soft Sample FORC diagram
Hard Sample FORC diagram
Biphase Sample FORC diagram
I-spot
E-spot
I-spot
E-spot
I-spots
E-spot