Magnetic Trapping of Atomic Nitrogen and Cotrapping of NH

We observe magnetic trapping of atomic nitrogen ($^{14}$N) and cotrapping of $^{14}$NH ($X^3\Sigma^-$). We use buffer gas cooling to load the magnetic trap directly from a room temperature molecular beam generated by a radio-frequency plasma source. We trap approximately $1 \times 10^{11}$ $^{14}$N atoms at a peak density of $5 \times 10^{11}$ cm$^{-3}$ at a temperature of $\approx$ 550 mK. The $1/e$ lifetime of nitrogen in the trap of 12 +5/$-3$ s is limited by collisions with the helium buffer gas. This lifetime sets a limit on the inelastic rate constant for $^{14}$N-$^3$He collisions of $\Gamma_{in} < 2.2 \times 10^{-16}$ cm$^3$\thinspace s$^{-1}$. $^{14}$N and $^{14}$NH are cotrapped, with $4 \times 10^{10}$ $^{14}$N atoms and $1\times 10^8$ $^{14}$NH molecules at peak densities of $n_{N} \approx 1 \times 10^{11}$ cm$^{-3}$ and $n_{NH} \approx 1 \times 10^{8}$ at a temperature of $\approx 550$ mK.