Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An upper bound for the magnetic force gradient in graphite   Cervenka et al. have recently reported ferromagnetism along graphite steps.
We present Magnetic Force microscopy (MFM) data showing that the signal along
the steps is independent of an external magnetic field. Moreover, by combining
Kelvin Probe Force Microscopy (KPFM) and MFM, we are able to separate the
electrostatic and magnetic interactions along the steps obtaining an upper
bound for the magnetic force gradient of about16 microN/m, a figure six times
lower than the lowest theoretical bound reported by Cervenka et al. Our
experiments suggest absence of MFM signal in graphite at room temperature.

31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs