### Abstract:

Research on the effect of the addition of copper concentration on the magnetic
susceptibility and morphological value of natural sand iron oxide nanoparticles taken
from Ulakan Pariaman Beach, West Sumatra Province has been carried out. The iron
and non iron oxide particles of sand sample was separated using an Iron Sand
Separator (ISS) then the product was separated again between iron and other iron
oxides using Neodymium Iron Boron (NdFeB) magnets, the result is called a NdFeB
product. The NdFeB product was milled through step one for 3 hours with mill balls
diameter of 1.5 cm as many as 18 balls, the result is called product BM 1. The product
BM 1 was separated from iron and other oxides using NdFeB magnets. The second
stage ball milling was done for 15 hours with the same milling balls, the result is
called BM 2 product. BM 2 product was separated again from iron and other oxides
using NdFeB magnets, then milled again for 102 hours with a combined diameter of
1.5 cm milling balls as many as 18 balls and 0.5 cm as many as 50 balls, the result is
called BM 3 product. BM 3 product was divided into 5 parts, then each part was
doped with Cu (copper) as a function of weight concentration using ball milling for
20 hours with the same milling ball diameter parameter, the result are called
composite nanoparticles (Fe3O4)100-xCux where x= 0 %; 5 %; 10 %; 15 %; and 20 %.
Magnetic susceptibility was calculated based on the value of the magnetic induction
of the solenoid (B0) and the total magnetic induction of the solenoid (BT) using the
Pasco PS-2162 magnetic probe as a function of current 200; 400; 600; 800; and 1000
mA. The results showed that the magnetic susceptibility decreased from 2524.04 x
10-5; 1931.66 x 10-5; 1897.32 x 10-5; 1828.64 x 10-5; and 1794.30 x 10-5 with the
addition of a copper weight concentration of 0 %; 5 %; 10 %; 15 %; and 20 %. The
size and shape of the iron oxide nanoparticles were determined by Scanning Electron
Microscope (SEM). The results of SEM analysis show that the particle size increases
with the addition of copper concentration (wt.%).