Handbook of Magnetic Measurements

Fundamentals of Magnetic Measurements 105

is linked with the uxes: Φ

1

= n

1

A

1

μ

0

H + n

1

A

m

J where

A

m

is the cross section of the specimen. If n

1

A

1

= n

2

A

2

,

the air ux is compensated and the resulting ux is

(Fiorillo 2004)

Φ = −

⎛

⎝

⎜

⎞

⎠

⎟

n A J

A

A

N

m

m

d1

1

1

(2.263)

In the case of magnetic thin lm, it is difcult to realize

magnetically closed sample and commonly the sample

is used in form of the circle. The circular sample is also

often used in magnetometric methods of investiga-

tions of magnetic materials (Humprey and Johnston

1963, Tejedor et al. 1985). For example, it is convenient

to use the circular sample for anisotropy measuremen ...